Not able to invoke BPM oData (taskdata.svc) service

Hello,

I am trying to access input/output data of a task using BPM oData service (taskdata.svc), but i am getting  "500 Internal Server Error" while accessing the same using below URL:

http://host:port/bpmodata/taskdata.svc/fc57eb8862f611e39b0800000058dd6a/InputData(‘fc57eb8862f611e39b0800000058dd6a’)?$expand=Message1/Record&$format=json

Error: An error occurred. 500 Internal Server Error. Log ID: C000AC112A030BF00000000000006F3B

Note - I am using PO SP09 and the potential owner of the task is already having "BPEM End User" and "UnifiedInboxUserRole" roles assigned to it.

In addition to that, i am able to retrieve metadata of a task using below URL (tasks.svc service), so i am wondering why the URL having taskdata.svc is not working?

http://host:port/bpmodata/tasks.svc/TaskCollection(‘fc57eb8862f611e39b0800000058dd6a’)?$format=json

Thanks

Amit Srivastava