SENDTASKDESCRPITION Method error in SELFITEM Object Type

Hi,

I have created a simple Workflow for testing a problem.It has only one step call sendtaskdescription method. I have done binding only Addresstring Parameter with WF Initiator. When i test i am getting error Error '9' when calling service 'SO_OBJECT_SEND'. The value of Addresstring is displaying as USSAPUSER. I cannot find out where is the problem.

Keenly waiting for your reply.

Thanks & Regards,

Bikash.