Problem in creating a PO from SOCO

Hi,

I am working on SRM 4.0 , classic scenario.

When I am trying to create a PO from SOCO , I am getting the following error messages

1) Partner xxxxxxxxxxxxxxxxxxxxxxxxxxxxx not found.

2) Enter a country for partner with type 'Preferred Vendor'

I checked the GUID of the vendor which I am entering while creating a PO with one which is displayed in error. Both GUID's are different.

Also when I search the GUID displayed in the error message in VENMAP table . there is no corrosponding entry in the table for this GUID.

I checked the org. unit of vendor , the country field is maintained for the same.

There is no preferred vendor maintained in the SC also. From where the system is picking up this message ?

I would also like to add , in monitor SC application when I look at the item detail the system displays the message " Address Data has been Changed ". But I can not see any changes in the SC history.

I also checked PO10 tx for changes in the org unit but nothing has been changed there also.

From where the system is picking up this preferred vendor and messages ?

Would appreciate your help on this .