RFQ workflow

Dear Experts,

I am using std workflow WS20000080 for RFQ. I have used rule 20000030 for agent assignment. Also I have made my task as general for all activity steps. But although i have made all settings in workflow side when i test it i am getting error in workflow log as "Element purchase order is not available in the container. Error in resolution of rule 'AC20000030' for step. Agent determination failed". I found a similar thread in forum that i given below. but there is no solution given for that thread.

[rfq-workflow-agent-assignment]

i used swu_obuf and then tested. I creating RFQ but Why does it look for purchase order in the error. kindly tell me what is that i am missing.

Kind Regards,

S Bharath