Robert - the same symptoms were reported by the IBM services team going from V9.0 -> V9.5.
LE Level 2 shot a dump for the U4088 RC78 from the IBM services team and had this to say:
This particular subcode '78' on the U4088 is
pretty unique. I've seen a lot of U4088's but that code is a strange
situation... defined as:
"The Get Next Available Byte service (CEEVGTUN) was invoked when the
stack direction was down."
CEEVGTUN is the routine to 'get user nab'... for non-xplink or upstacks
which use a NAB (next available byte) to point the next available stack
up the segment...yet the call was done when in an XPLINK (downstack)
routine. Quite odd.
That's just trivia --- that it's an interesting error.
Now, a possible solution:
SARSINST(ARSUUPDT) and SARSINST(ARSUUPDC) provide the same functionality for the arsuupdt exit. One is in C and one is in COBOL. Either one calls the ARSUUPDX program. The arsuupdt we provide is compiled XPLINK. I think you'll need to use a non-xplink arsuupdt.
If you compile the COBOL ARSUUPDC, that would be a non-xplink arsuupdt. That non-xplink arsuupdt would call ARSUUPDX with an upstack environment. SARSINST(ARSUUPDJ) can be used to compile SARSINST(ARSUUPDC) into the exits/arsuupdt.
Be aware that any maintenance IBM ships to arsuupdt will overwrite the exits/arsuupdt - you'll probably want to use ARS_USER_EXITS_DIR= to have it reside somewhere else but it's not mandatory.
This problem was never closed with a firm answer....it just sort of faded away.
One of the last comments was that ARSUUPDX had to be in dataset SARSEXIT in the STEPLIB concatenation ahead of SARSLOAD.
Hope this helps.
Ed