When you create a rebate credit memo, an error occurs:
VK304 "Error creating rebate credit memos (see next warning message)"
Afterwards one of the following error messages can occur:
"Sold-to party & not maintained for sales area & & &"
"Sales document type & is not defined".
The error is caused by an external perform in program SAPFV45K in user exit (RV60AFZZ)
USEREXIT_PRICING_PREPARE_TKOMK or USEREXIT_PRICING_PREPARE_TKOMP.
This causes memory area conflicts which then cause errors that are difficult to track.
Search in the two user exits in program RV60AFZZ for external calls PERFORM <routine_xyz>(SAPFV45K) and remove these.