I am also Getting same issue like this when an user of particular group like approver going to apporve his take then i am getting this exception, I'm using R2 SP2. please help me..asap
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.NullReferenceException: Object reference not set to an instance of an object. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
I'm using the Parallel Approval workflow and it works as expected if I assign users as approvers. If I select a group (containing the same users) however, the workflow does not start at all. Am I missing something or is this a bug? I'm using R2 SP2.