Problem regarding Individual Purchase Order

Hi all ,

actually faced a problem when running individual PO scenario .

Make the material ( HAWA material type )  with settings , like , item. category group - BANC , mrp group - 20 , special procurement - 20 , procurement type - F , strategy group - 20 (MTO ) .

I made the sales order  with TAB itm cat, - the purchase requisition was generated and them generate the PR by ME5A ... then , generate PO .

when , PO was generated an error is displayed - like , sales document item is not defined for this transaction

Message no. V1198 ...

my query - I've done most of necessary settings correct , then why this error message displayed ?

regards

patel