Message SAP WS448 - An internal error occurred

Diagnosis
An internal error occurred.

System Response
The function is terminated.

Procedure
INCLUDE ISR_VERWALTUNG

Procedure for System Administration
No interest rates are defined for interest calculation indicator &V1&in Customizing. Check the Customizing settings for interest inDefine interest rates under Dunning. Ifnecessary, contact SAP. The error relates to sub-program"get_percentage_for_vendor" in function group WLFV.