40A

Explanation
An error occurred when the system tried to process
an R form of the FREEMAIN macro. A reason code in the SDWACRC field
of the system diagnostic work area (SDWA) explains the error: Code
Explanation
04
The caller tried to FREEMAIN a subpool that cannot be freed. Only
subpools defined as eligible for subpool FREEMAIN may be freed as
an entire subpool.  All other subpool storage areas must be freed
by individual requests explicitly describing the area.

08
A problem program tried to free subpool zero.  The control program
releases subpool zero when a job step ends.

System action
The system issues message IEA705I. The system
abnormally ends the current task.

Programmer response
If you intended the FREEMAIN macro to release
subpool zero, remove it from the program. If you did not intend the
FREEMAIN macro to release subpool zero, check for program errors that
incorrectly modify the FREEMAIN macro expansion. After making corrections,
run the job step again.

Source
Virtual storage manager (VSM)