I'm getting an error message periodically: attempt to de-reference a null object on line 79 column 13.  Can someone tell me what's wrong?

• trigger leadRoundRobin on Lead (before insert, before update) {
      //
      //Check if assignment owner has changed
      //
      Map<Integer,Id> queueIds = new Map<Integer,Id>();   //Trigger index --> Queue ID
      
      Integer idx = 0;
      for (Lead cs : Trigger.new)
      {
          if(Trigger.isUpdate) {  
              if(cs.OwnerId <> Trigger.oldMap.get(cs.id).OwnerId) {
                  if (cs.TempOwnerId__c == 'SKIP') {
                      Trigger.new[idx].TempOwnerId__c = '';
                  } else {
                      queueIds.put(idx, cs.OwnerId);
                  }
              }           
          }else {
              queueIds.put(idx, cs.OwnerId);
          }   
          idx++;
      }
      System.debug('>>>>>queueIds: '+queueIds);
      if (queueIds.isEmpty()) return;
      
      //
      //Find active Assignment Group for Queue
      //
      Map<Integer,Id> asgnGroupNameIds = new Map<Integer,Id>();   //Trigger index --> Assignment_Group_Name ID
      Map<Id,Assignment_Group_Queues__c> asgnGroupQueues = new Map<Id,Assignment_Group_Queues__c>(); //Queue ID --> Assignment Group Queues
      
      for(Assignment_Group_Queues__c[] agq : [SELECT Assignment_Group_Name__c, QueueId__c
                                            FROM Assignment_Group_Queues__c 
                                            WHERE QueueId__c in :queueIds.values()
                                            AND Active__c = 'True'])
      {
          for (Integer i = 0; i < agq.size() ; i++) {
              asgnGroupQueues.put(agq[i].QueueId__c, agq[i]);
          }                                           
      }
      System.debug('>>>>>asgnGroupQueues: '+asgnGroupQueues); 
      if (asgnGroupQueues.isEmpty()) return;
  
      for (Integer i : queueIds.keySet()) {
          Assignment_Group_Queues__c agq = asgnGroupQueues.get(queueIds.get(i));
          
          if (agq <> null) {
              asgnGroupNameIds.put(i, agq.Assignment_Group_Name__c);
          }
          //else no active assignment group queue error
      }
      System.debug('>>>>>asgnGroupNameIds: '+asgnGroupNameIds);
      if (asgnGroupNameIds.isEmpty()) return;
      
      //
      //Determine next valid user in Queue/Assignment Group for round robin
      //User with earliest last assignment date wins.
      //
      Map<Id,Assignment_Groups__c[]> asgnGroups = new Map<Id,Assignment_Groups__c[]>(); // Assignment Group Name ID --> User ID
      for(Assignment_Groups__c[] ags : [SELECT Group_Name__c, User__c, Last_Assignment__c, Millisecond__c 
                                     FROM Assignment_Groups__c 
                                     WHERE Group_Name__c in :asgnGroupNameIds.values() 
                                     AND Active__c = 'True' AND User_Active__c = 'True'
                                     ORDER BY Last_Assignment__c, Millisecond__c])
      {
          if (ags.size()>0) {
              asgnGroups.put(ags[0].Group_Name__c, ags);
          }
      }
      System.debug('>>>>>asgnGroups: '+asgnGroups);   
      if (asgnGroups.isEmpty()) return;
  
      Map<Id,Assignment_Groups__c> updateAssignmentGroups = new Map<Id,Assignment_Groups__c>();
      Map<Id, datetime> latestAGDateTime = new Map<Id,datetime>();
      idx = 0;    
      for (Integer i : queueIds.keySet())
      {
          Assignment_Groups__c[] ags = asgnGroups.get(asgnGroupNameIds.get(i));
   if (ags.size()>0)
          {   
              //Choose next user in line if user ID has already been used but not committed in this trigger batch 
              Assignment_Groups__c ag = ags[math.mod(idx, ags.size())];
                  
              //Assign User to Lead as the new owner
              System.debug('>>>>>Owner changed for Lead ' + Trigger.new[i].Id + ' from '+Trigger.new[i].OwnerId+' to '+ ag.User__c);
              Trigger.new[i].OwnerId = ag.User__c;    
              Trigger.new[i].TempOwnerId__c = ag.User__c; 
  
              //Set last assignment datetime
              datetime now = datetime.now();
              ag.Last_Assignment__c = now;
              ag.Millisecond__c = now.millisecondGMT();
              
              //update only latest Assignment Groups per ID
              if (latestAGDateTime.containsKey(ag.id)) {
                  if(latestAGDateTime.get(ag.id) < now) {
                      updateAssignmentGroups.put(ag.id, ag);
                      latestAGDateTime.put(ag.id, now);
                  }
              } else {
                  updateAssignmentGroups.put(ag.id, ag);
                  latestAGDateTime.put(ag.id,now);
              }
              
              idx++;
          }
      }
      //Map --> List/Array for DML update
      List<Assignment_Groups__c> updateAG = new List<Assignment_Groups__c>();
      for (Id agId : updateAssignmentGroups.keySet()) {
          updateAG.add(updateAssignmentGroups.get(agId));
      }
  
      System.debug('>>>>>Update Assignment Groups: '+updateAG);   
      
      //
      //Update last assignment for Assignment Group in batch
      //
      if (updateAG.size()>0) {
          try {
              update updateAG;
          } catch (Exception e){
              for (Integer i : queueIds.keySet())
              {
                  Trigger.new[i].addError('ERROR: Could not update Assignment Group records ' + ' DETAIL: '+e.getMessage());  
              }
          }
      }
  }

I'm getting an error message periodically: attempt to de-reference a null object on line 79 column 13.  Can someone tell me what's wrong?

• trigger leadRoundRobin on Lead (before insert, before update) {
      //
      //Check if assignment owner has changed
      //
      Map<Integer,Id> queueIds = new Map<Integer,Id>();   //Trigger index --> Queue ID
      
      Integer idx = 0;
      for (Lead cs : Trigger.new)
      {
          if(Trigger.isUpdate) {  
              if(cs.OwnerId <> Trigger.oldMap.get(cs.id).OwnerId) {
                  if (cs.TempOwnerId__c == 'SKIP') {
                      Trigger.new[idx].TempOwnerId__c = '';
                  } else {
                      queueIds.put(idx, cs.OwnerId);
                  }
              }           
          }else {
              queueIds.put(idx, cs.OwnerId);
          }   
          idx++;
      }
      System.debug('>>>>>queueIds: '+queueIds);
      if (queueIds.isEmpty()) return;
      
      //
      //Find active Assignment Group for Queue
      //
      Map<Integer,Id> asgnGroupNameIds = new Map<Integer,Id>();   //Trigger index --> Assignment_Group_Name ID
      Map<Id,Assignment_Group_Queues__c> asgnGroupQueues = new Map<Id,Assignment_Group_Queues__c>(); //Queue ID --> Assignment Group Queues
      
      for(Assignment_Group_Queues__c[] agq : [SELECT Assignment_Group_Name__c, QueueId__c
                                            FROM Assignment_Group_Queues__c 
                                            WHERE QueueId__c in :queueIds.values()
                                            AND Active__c = 'True'])
      {
          for (Integer i = 0; i < agq.size() ; i++) {
              asgnGroupQueues.put(agq[i].QueueId__c, agq[i]);
          }                                           
      }
      System.debug('>>>>>asgnGroupQueues: '+asgnGroupQueues); 
      if (asgnGroupQueues.isEmpty()) return;
  
      for (Integer i : queueIds.keySet()) {
          Assignment_Group_Queues__c agq = asgnGroupQueues.get(queueIds.get(i));
          
          if (agq <> null) {
              asgnGroupNameIds.put(i, agq.Assignment_Group_Name__c);
          }
          //else no active assignment group queue error
      }
      System.debug('>>>>>asgnGroupNameIds: '+asgnGroupNameIds);
      if (asgnGroupNameIds.isEmpty()) return;
      
      //
      //Determine next valid user in Queue/Assignment Group for round robin
      //User with earliest last assignment date wins.
      //
      Map<Id,Assignment_Groups__c[]> asgnGroups = new Map<Id,Assignment_Groups__c[]>(); // Assignment Group Name ID --> User ID
      for(Assignment_Groups__c[] ags : [SELECT Group_Name__c, User__c, Last_Assignment__c, Millisecond__c 
                                     FROM Assignment_Groups__c 
                                     WHERE Group_Name__c in :asgnGroupNameIds.values() 
                                     AND Active__c = 'True' AND User_Active__c = 'True'
                                     ORDER BY Last_Assignment__c, Millisecond__c])
      {
          if (ags.size()>0) {
              asgnGroups.put(ags[0].Group_Name__c, ags);
          }
      }
      System.debug('>>>>>asgnGroups: '+asgnGroups);   
      if (asgnGroups.isEmpty()) return;
  
      Map<Id,Assignment_Groups__c> updateAssignmentGroups = new Map<Id,Assignment_Groups__c>();
      Map<Id, datetime> latestAGDateTime = new Map<Id,datetime>();
      idx = 0;    
      for (Integer i : queueIds.keySet())
      {
          Assignment_Groups__c[] ags = asgnGroups.get(asgnGroupNameIds.get(i));
   if (ags.size()>0)
          {   
              //Choose next user in line if user ID has already been used but not committed in this trigger batch 
              Assignment_Groups__c ag = ags[math.mod(idx, ags.size())];
                  
              //Assign User to Lead as the new owner
              System.debug('>>>>>Owner changed for Lead ' + Trigger.new[i].Id + ' from '+Trigger.new[i].OwnerId+' to '+ ag.User__c);
              Trigger.new[i].OwnerId = ag.User__c;    
              Trigger.new[i].TempOwnerId__c = ag.User__c; 
  
              //Set last assignment datetime
              datetime now = datetime.now();
              ag.Last_Assignment__c = now;
              ag.Millisecond__c = now.millisecondGMT();
              
              //update only latest Assignment Groups per ID
              if (latestAGDateTime.containsKey(ag.id)) {
                  if(latestAGDateTime.get(ag.id) < now) {
                      updateAssignmentGroups.put(ag.id, ag);
                      latestAGDateTime.put(ag.id, now);
                  }
              } else {
                  updateAssignmentGroups.put(ag.id, ag);
                  latestAGDateTime.put(ag.id,now);
              }
              
              idx++;
          }
      }
      //Map --> List/Array for DML update
      List<Assignment_Groups__c> updateAG = new List<Assignment_Groups__c>();
      for (Id agId : updateAssignmentGroups.keySet()) {
          updateAG.add(updateAssignmentGroups.get(agId));
      }
  
      System.debug('>>>>>Update Assignment Groups: '+updateAG);   
      
      //
      //Update last assignment for Assignment Group in batch
      //
      if (updateAG.size()>0) {
          try {
              update updateAG;
          } catch (Exception e){
              for (Integer i : queueIds.keySet())
              {
                  Trigger.new[i].addError('ERROR: Could not update Assignment Group records ' + ' DETAIL: '+e.getMessage());  
              }
          }
      }
  }

This seems easy enough, but it has me stumped.

Use Case: Partners create leads in the partner portal. When the lead is ready to convert, our reps change themselves to the owner and convert it. I want to automatically add (since they forget all the time) the partner user to the sales team.

Problem: When I convert the lead (i have the trigger running after insert) I get an error saying that the record is locked.

It looks to me like Salesforce inserts the opportunity record, but locks it so its uneditable through the conversion. My trigger also depends on a custom field being mapped over, so that's why I run the trigger after insert so that the field will be mapped over.

Any thoughts anyone on how to get around this?

Here's my code:

 trigger addPartnerToSalesTeam on Opportunity (after insert) {
    
    /**
    * Need to get the opportunity and user
    */
    private Opportunity[] newOpty = new Opportunity[1];
    newOpty = Trigger.new;    

    //get userId of lead creator
    String leadCreatorId = newOpty[0].Lead_Creator_Id__c;

    //get lead Creator profile Id
    User leadCreator = [select profileId from user where id =:leadCreatorId];
    
    newOpty[0].description = leadCreator.ProfileId;//testing
    
    //run trigger if the owner of the converted lead was a partner user
    if(leadCreator.ProfileId == '00e20000000uCnj') {
        newOpty[0].description = newOpty[0].description + ' It works!!!' + ' ' + leadCreatorId; //for testing
        addtoSalesTeam.addUser(newOpty[0], leadCreatorId);

    }//end if

        
}//end addPartnerToSalesTeam trigger

 ________________________________________________________________

 public class addToSalesTeam {
    
    /**
    * To run this method, the trigger (or whatever calls it) must pass two variables:
    *
    * @Opportunity opty = the opportunity being shared
    * @User theUser = the user to be shared with
    *
    */
    public static void addUser (Opportunity opty, String userId) {
        
        OpportunityTeamMember optyMemb = new OpportunityTeamMember();

        optyMemb.OpportunityId = opty.Id;       

        optyMemb.UserId = userId;     

        Database.Saveresult sr = Database.insert(optyMemb);

    }//end addPartner method

}//end AddToSalesTeam