Hi,
I have a requirement to create a new account(if the entered account doesn't exist already) every time a contact is created/edited from ETL (The ETL profile user) 

    public static void createAutoVendor(List<Contact> contList, boolean isInsert, boolean isUpdate, Map<Id, Contact> oldContacts){
        Set<Id> existingAccs = New Set<Id>();
        Set<String> existingAccNames = New Set<String>();
        List<Account> newAccs = New List<Account>();
        Map<String, Id> mapAccToCont = New Map<String, Id>();
        Id createdBy=[SELECT Id FROM User WHERE Name  = 'ETL User'].id;
                
        //Select all the existing Accounts and add them to the Set of Accounts
        for (Account acc:[SELECT Id, Name FROM Account]){
            existingAccs.add(acc.id);
            existingAccNames.add(acc.Name);
        }
        for (Contact con:contList){
            if(con.Vendor__c <> null){  //Vendor__c is the name of the account in ETL

                if(((isInsert && con.CreatedById==createdBy) ||
                   (isUpdate && con.LastModifiedById==createdBy 
                    && con.Vendor__c<>oldContacts.get(con.Id).Vendor__c))
                  && (!existingAccNames.contains(con.Vendor__c))){
                       Account Acc = New Account(name=con.Vendor__c, Type='Vendor'); //Create a new Account if it's not existing already
                       newAccs.add(Acc);

                   }
                insert newAccs;

            }            
        }
        for (Account acc:newAccs){
            mapAccToCont.put(acc.Name, acc.Id);

        }
        for (Contact con:contList){
            if(mapAccToCont.containsKey(con.Vendor__c)){
                con.AccountId=mapAccToCont.get(con.Vendor__c);

            }
        }        
    }

This code is working when I am running from the "Execute Anonymous Window" as an Admin. But failing from ETL with following error:
System.DmlException: Insert failed. First exception on row 0; first error: CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY, ContactTrigger: execution of BeforeInsert

Any help in this regard is really appreciated.