I had the same problem today

I was running a program from another Project that relied on a Linkage Section value being passed that was not actually passed because I had taken the program out into another Project without really looking closely enough at the requirements

The compile was fine but the run found the problem

Does your program require something from another program that was not supplied?

If so, then the 'null' Linkage Section field name might have been low values or something else

Worth checking

Run it with DEBUGGING ON on so you can see which instruction had the problem