SAP Note 15790 - Cancellation RV_MESSAGE_UPDATE with TD456 : page format

Symptom:

When trying to post a document, you receive a posting cancellation in the module RV_MESSAGE_UPDATE with TD456 (message: A456): Form & has the wrong page format..
Example: Goods receipt to a purchase order assigned to an account. You receive the above error message for form MB_MFKTO .

Cause and prerequisites

The page format must not be changed when formatting a form that is started with open_form and ends with close_form. The page format of the first form is decisive.

Solution
Change the page format for the form in question to the page format of the first form using SE71.
Referring to the above example: enter the page format of the goods receipt slip into form MB_MFKTO.