42D

Explanation
While an overlay program was running, an error
occurred in the processing of a SEGLD macro.
Note: Overlay programs
run only in 24-bit addressing mode, not in 31-bit addressing mode.

System action
The system abnormally ends the program that requested
the overlay.  The system writes an ABEND dump, if a dump DD statement
is provided.

Programmer response
Obtain the address in register 12 at the
time of the error. Add X'14' to the address to find the address
of the event completion block (ECB) that contains the subtask completion
code.
Look for errors in the program.  Correct the errors; then
assemble, link edit, and run the program again.

Source
Overlay supervisor