Cross-company stock transfer with delivery function!

Dear friends:

I have a problem to borther u,I create stock transfer order with type 'NB',and then create delivery by T-CODE:VL10B with reference to the transfer order,but the log show the following error message:

1030000484 000010 Sales unit is not valid for item 000010

Diagnosis

The sales unit is not allowed for the material in item

000010.

System Response

The system does not allow further processing of this item.

Procedure

Check your entry.

Select a sales unit which is defined for the material in the

material master record. Normally the sales unit will be

determined immediately from the master master record.

I really don't know how to deal it.

thanks.