OK, after a day of investigating and installing version 5.1 several times and copying 5.07 dlls to 5.1, I have found the problem.
The problem was in the OS2\dll directory. It was one file. The file is
dspres.dll
The one found in version 5.1 is 455,064 bytes
The one found inversion 5.07 is 395,096 bytes
There were some updates made to DSPRES.DLL in 5.1, yes.
I wonder if I might ask you to try both of the attached versions of DSPRES.DLL and see if they exhibit the same problem or not. (They both have a different subset of the additions made for 5.1.)
Hi Alex
I tried them both. They both create the same OpenChat trap as the original one included with 5.1. I switched back to the 5.08 version and OpenChat works just fine. So far, OpenChat is the only program that traps when using the new dlls.
11-14-2023 07:25:34 SYS3184 PID 0044 TID 0001 Slot 0070
E:\PROGRAMS\OPENCHAT\OPENCHAT-SMP.EXE
c000009b
000479c6
EAX=fffffff3 EBX=00000003 ECX=00000000 EDX=ffffffff
ESI=fffffff3 EDI=1b34e3f4
DS=0053 DSACC=d0f3 DSLIM=5fffffff
ES=0053 ESACC=d0f3 ESLIM=5fffffff
FS=150b FSACC=00f3 FSLIM=00000030
GS=0000 GSACC=**** GSLIM=********
CS:EIP=005b:000479c6 CSACC=d0df CSLIM=5fffffff
SS:ESP=0053:000f86a8 SSACC=d0f3 SSLIM=5fffffff
EBP=000f8ffe FLG=00010287
OPENCHAT-SMP.EXE 0003:000179c6
Attached is a picture of OpenChat when it works to give you an idea of the fonts used.