Create object : Candidate__c
Fields : (All Text fields)
First Name
Last Name
Email
Brokerage
Manage Brokerage
Candidate Status (Webinar - Attended , Webinar -Not Attended)
User Created ( checkbox)


On insert:
1. Create Account if Brokerage !=null
2. Create another account if Manage Brokerage != null and set parentId = Brokerage account id (created in 1 point)
3. Create new contact record and set accountId = Manage Brokerage account id (created in 2 point)
   create new field candidate__c(lookup) on contact and fill it with Condidate__c record id
4. Create task record for contact record (created in point 3)
Task.WhoId = contactId
Task.WhatId = Candidate__c
Task.Subject = 'Portal Contact Setup';

The line which is commented is giving me a DML exception dont know why? i think it is not getting id there.. I know i am asking too many questions or may be silly questions but i want some clear point on these.

public static void brokeragePortal(List<Candidate_Brokerage__c> candBrokRecords){
        Map<id, Contact> contListMap = new Map<id, Contact>();
        Map<id, Account> accListMap = new Map<id, Account>();
        Map<id, Account> newAccListMap = new Map<id, Account>();
        Map<id, Task> taskListMap = new Map<id, Task>();
                
        for(Candidate_Brokerage__c brokerCand: candBrokRecords){   
            if(brokerCand.Brokerage__c != NULL){
                Account acc = new Account(name = 'Brokerage Account');
                if(!accListMap.containsKey(brokerCand.id)){
                    accListMap.put(brokerCand.id, acc);
                }                
            }
        }
        if(accListMap.values().size()>0){
            insert accListMap.values();
        }
        for(Candidate_Brokerage__c cand: candBrokRecords){
            if(cand.Brokerage__c != NULL && cand.Manage_Brokerage__c != NULL){
                Account manageBrokAcc = new Account(name = 'Manage Brokerage Account');
                if(accListMap.containsKey(cand.id)){
                    manageBrokAcc.ParentId = accListMap.get(cand.id).id;
                }
                if(!newAccListMap.containsKey(cand.id)){
                    newAccListMap.put(cand.id, manageBrokAcc);
                }
                Contact newContact = new Contact(lastName = 'John Doe');
                if(!contListMap.containsKey(cand.id)){
                    contListMap.put(cand.id, newContact);
                }
            }
        }
        if(newAccListMap.values().size()>0){
            insert newAccListMap.values();
        }
        if(contListMap.values().size()>0){
            insert contListMap.values();
        }
        for(Candidate_Brokerage__c cand: candBrokRecords){
            if(cand.Brokerage__c != NULL && cand.Manage_Brokerage__c != NULL){
                Task newTask = new Task();
                if(contListMap.containsKey(cand.Id)){
                    newTask.WhoId = contListMap.get(cand.Id).id;
                }
                //newTask.WhatId = cand.id;
                newTask.Subject = 'Portal Contact Setup';
                if(!taskListMap.containsKey(cand.Id)){
                    taskListMap.put(cand.id, newTask);
                }
            }
        }
        if(taskListMap.values().size()>0){
            insert taskListMap.values();
        }
    }
//Trigger
trigger BrokerageTrigger on Candidate_Brokerage__c (after insert) {
    if(Trigger.isAfter && Trigger.isInsert){
    	AccountContact.brokeragePortal(Trigger.new);    
    }
}