AWE - ApprovalManager.GetAllActiveParticipants() - Method GetAllActiveParticipants is NOT returning

Here is the scenario,

I'm trying to interact directly with the ApprovalManager for a Requisition transaction and in doing so would like a list of all Pending approvers on the transaction.  For those approvers with pending approvals still outstanding, I'll be reassigning thier work  to a high level administrator.

I'd like the interaction to remain at the ApprovalManager level and not have to interact with the Base classes of the package if possible.  One method, GetAllActiveParticipants, seems to fit the bill exactly, however when implemented and called for a new Requisition with Pending approvals, the process is receiving a PeopleCode error: