It seems that someone has found a solution on Steam, specifically user wendigo211:
https://steamcommunity.com/app/2350550/discussions/0/3806156528941628171/
Okay, I got the game (GoG version) to stop crashing following Nobody's instructions. The crashes do seem to be caused by improper sound file configuration. I'll go into a bit more detail.
If you get crashes whenever certain enemies attack (e.g. Umberhulk or Undead) 1- Open up the spelljam-eng-base.conf file in a text editor (e.g. notepad) it will be in the Spelljammer Pirates of Realmspace base directory.
2 - find the line:
sbtype=sbpro2 3 - change it to:
sbtype=sb16 4 - save the file and this problem should be resolved.
If you get crashes whenever you click loot at the end of a battle
1 - From the Spelljammer Pirates of Realmspace base directory [...] navigate to ...\DOSBOX and double click on DOSBox.exe to open a DOSBox window.
2 - In the DOSBox window type mount c c:\, assuming the Spelljammer Pirates of Realmspace base directory is on your c drive, if it's on another drive (e.g. d) type mount c d:\ instead.
3 - Type c:\ to change to the c drive and now comes the fun part of navigating to the Spelljammer Pirates of Realmspace\GAME\SPELLJAM directory using no white space 8 character limit directory names. Take it directory by directory as you trace the path. Use the cd command to change directory and dir /w to display the contents of the current directory. E.g. If you need to change to the Program Files (x86) directory, you'll have to type something like: cd progra~2. If you end up in the wrong directory type cd .. to go back up one level.
4 - Once you're in the right directory, type SOUND to execute SOUND.EXE.
5 - Hit 7 to change the sound to: LAPC music, Soundblaster Pro Sound Effects
6 - Exit the sound program and you're done.
