Diagnosis
Contract account &V1& of partner &V2& is already paid via accountaccount &V3& of partner &V4&.
You cannot pay a contract account via an account that is itself paid viaa clearing account. Neither can you assign a clearing account to acontract account if this contract account is already defined asclearing account in another account.

Procedure
Delete the clearing account you have entered, choose a permittedclearing account, or change the contract account &V1& of partner &V2&.