No IDoc items belonging to purchasing document found

Hi,

I have used standard Output type NEU and selected the Medium as EDI. I have changed the PO, it is giving the error "No IDoc items belonging to purchasing document found". I am using the message type PORDCH for outbound.

The message control is given below.

I have changed the fields like quanity and net price but no luck..

Can you please help me to resolved this issue?

Thanks

Srini