SAP Message U6009 - &1 is not a valid function module

Diagnosis
In the solution paths table, a solution path has been entered forthe cause &V4& of error &V2& &V3&.
The table modules for solutions contains &V1& as an ABAP functionmodule. However, a function module with this name does not exist.

Procedure
Check entry &V1& in table modules for solutions ( =ISU_SOLMODULES ).