This & program cannot be executed (Include?)

What causes this issue?

The program stipulated is neither an executable program nor a module
pool.

System Response

Only executable programs have screens. A field selection can only be
defined for an executable program.

How to fix this error?

Enter the name of the program for which the screens have been defined.
If you have given the name of an include program by mistake, find out
the name of its program and enter that.

Error message extract from SAP system. Copyright SAP SE.