Diagnosis
You want to allocate costs between two account assignment objectsbelonging to different company codes.
Here, you refer to a posting row in an accounting document. However,since debit and credit rows cannot belong to different company codes,the cross-company-code posting cannot be carried out here.

Procedure
Check the receiver object.
If you wish to make cross-company-code postings in CO, use the actualposting transaction Repost costs.