Purchase requisition

Hi,

I created a vendor and I created Info record as a Subcontract and while I am creating the Purchase requisition I choosed the following things..

Purchase requisition standard after that I choosed the Item category is L( subcontracting) and I enter the Material ,Plant SLoc,quantity..etc..

And it showa the available vendos list Source of supply tab but the record is not saving it shows the error..That error is " Not possible to determine any components "

Could u plz give the suggestions for what I have to do to solve this error.

Thanks & Regards,

Sudheer