42A

Explanation
During processing of an ATTACH macro, the system
found that the ECB parameter specified an incorrect address for the
event control block (ECB) to be posted when the subtask abnormally
ends.
The address was incorrect for the following reasons: It was not on a fullword boundary.
The addressed virtual storage is not allocated, or its protection
key does not match the protection key of the issuer of the ATTACH.

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

System programmer response
If the error recurs and the program
is not in error, look at the messages in the job log for more information.
Search problem reporting data bases for a fix for the problem. If
no fix exists, contact the IBM® Support
Center. Provide the program listing for the job.

Programmer response
Change the ATTACH macro to specify the correct
ECB address and ensure that the specification was not incorrectly
modified by the problem program. Correct the error.  Run the job again.

Source
Task management