"Automatic Storage Overflow"?

I have never seen of heard of this error before and I am not seeing anything
in the archives for the past couple years on it. We are on V5R3. This
program was working flawlessly until this morning. Ideas on where to start?
I am going to do a debug to see if I find anything.

CALL PGM(NCLIBR/NCPOSTACTC) PARM('0800451' '001')
Library NCLIBR added to library list.
Automatic storage overflow.
Function check. MCH4429 unmonitored by NCLIB at statement 0000000648,
instruction X'0000'.
The call to POSTACTION ended in error (C G D F).



Message ID . . . . . . : MCH4429

Date sent . . . . . . : 03/26/08 Time sent . . . . . . : 11:30:38



Message . . . . : Automatic storage overflow.



Cause . . . . . : One of the automatic storage stacks X'00000002' for the

thread has overflowed or a storage access beyond the maximum size of a

teraspace automatic storage stack was attempted. Further program execution

within the thread is not possible. Automatic storage stack values and
their
meanings follow:

1 -- System stack in single level storage.

2 -- User stack in single level storage.

3 -- System stack in teraspace.

4 -- User stack in teraspace.

Technical description . . . . . . . . : Attempt to reduce the automatic

storage used by programs running in the thread.