Getting Exceptions while using SENDTASKDESCRIPTION method

Hi

While debugging the above method i am getting ERROR Document not sent. I have imported User Id and Type 'G'. I have check the SWU3 and got Maintain Domain is mentioned correctly.

Another thing i must mention that if TYPEID is 'U' Error is _result is Persistent.

But when i see in Workflow Task in _Result, it displays ObjectSent = X.

Thanks,

Bikash.