Input parameter IT_ABWAPOLPR empty

What causes this issue?

The input parameter IT_ABWAPOLPR for the method
/PM0/IF_3F_BPP_ACTIVITY~EXECUTE in class /PM0/CL_ALP_BCPROJ_SRVCS_BT is
not filled.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.