We are receiving the following error message from one of the Apex Triggers set up by a consultant:

Apex script unhandled trigger exception
TaskBeforeInsertUpdate: execution of BeforeInsert
caused by: System.NullPointerException: Attempt to de-reference a null object
Trigger.TaskBeforeInsertUpdate: line 61, column 1

I have also attached line 61 of the code in the system. Can someone tell me what is causing this error?

                    t.Subject = t.Subject + ' - ' + IdContactMap.get(t.WhoId).Name;

We are receiving the following error message from one of the Apex Triggers set up by a consultant:

Apex script unhandled trigger exception
TaskBeforeInsertUpdate: execution of BeforeInsert
caused by: System.NullPointerException: Attempt to de-reference a null object
Trigger.TaskBeforeInsertUpdate: line 61, column 1

I have also attached line 61 of the code in the system. Can someone tell me what is causing this error?

                    t.Subject = t.Subject + ' - ' + IdContactMap.get(t.WhoId).Name;