52A

Explanation
During processing of an ATTACH macro, the system
found an error in the subtask ABEND intercept (STAI) or the extended
STAI (ESTAI) routine.
Register 15 contains a hexadecimal reason
code that explains the error: Code
Explanation
00
There is not enough storage available to create a new ESTAI specify
task asynchronous exit (STAE) control block (SCB) or to copy existing
STAI or ESTAI SCBs to the new task.
04
The issuer of ATTACH is processing with AMODE 31 and requested
STAI.  STAI is not supported for AMODE 31 callers.

System action
The system abnormally ends the program that issued
the ATTACH macro.

System programmer response
Search problem reporting databases
for a fix for the problem. If no fix exists, contact the IBM® Support Center.

Programmer response
Reason code 00 indicates a probable system
error.  Notify the system programmer.
For reason code 04, identify
the program that issued the ATTACH macro.  If an installation-provided
program issued the ATTACH, change the macro parameter from STAI to
ESTAI. If an IBM-provided program issued the ATTACH, notify the system
programmer.

Source
Task management