EQA2415I z/OS® Debugger could not stop at one or more instructions because a valid save area backchain was not found. At location LOCN.

Explanation

While debugging a program, z/OS Debugger could not stop the application because a valid save area back chain did not exist. The back chain pointer is located at +4 in the save area pointed to by register 13. This will most likely occur when stepping through the prolog code of a Compile Unit.