Specify a schema with a conditional billing program

What causes this issue?

You have specified in rate category &v2& that a conditional billing
program can be executed.
However, the schema &v1& does not allow a conditional billing program to
be executed.

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?

Specify a schema for which a conditional billing program can be
executed.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.