B2D

Explanation
A program requested an overlay.  In answer to the
request, the overlay supervisor was using program fetch to load a
program segment from the library.  While the fetch recovery routine
was processing because of a previous abend, a program check occurred.
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
Check the linkage editor input to be sure
the program is designed correctly.  Correct the errors; then assemble,
link edit, and run the program again.

Source
Overlay supervisor