I think I have solved the sound crash bug in The Solon Heritage for Vista and 7, but I need confirmation from others to see if it works. (It works for me)
LOI - Legions of Iron
TSH - The Solon Heritage
Here's what I did: (MAKE SURE TO BACK UP THE FILES THAT WILL BE OVERWRITTEN OR REMOVED!)
In both game directories, there is a folder called Inf.
In Haegemonia - The Solon Heritage\Inf\, I removed these files:
cachedsounds
music
ScreenSounds
sounds
Sounds_English
Sounds_French
Sounds_German
Sounds_Hungarian
Sounts_Italian
Sounds_Japan
Sounds_Polish
Sounds_Russian
Sounds_Spanish
After removing those files, I went to Haegemonia - Legions of Iron\Inf\ and copied these files:
cachedsounds
music
sounds
Copy these files into TSH version of the Inf directory and it should stop crashing.
As a side note during my experimentation, I also copied the Sound directory from LOI into TSH directory (overwriting all of the files). This copy was done BEFORE the fix outlined above and the game STILL crashed. I don't think it plays any part of actually fixing the problem, but I thought I'd mention that it was done prior to my experimentation with the Inf files.
I don't know which Inf file is the offender, but all I know is that I played the game for about 3 hours without a crash (as opposed to it working for only 10 minutes before crashing) before replacing the Inf files.
If anyone else who experiences the sound crash could verify this for me, I'd appreciate it. Thanks,

Nevermind, this solution doesn't work for me anymore :(

So.
did you got anything new?
if i find a solution will defo let you know about it...

Hey Twin. I haven't found a way to make it work. But it sure would be nice if gog.com could offer some insight with this issue instead of ignoring the tech support pleas.

There's a solution going about disabling speech, I have no idea how or where you do such thing, but it's said to fix it on some mod Website called Vector PRime

Thank you Mr. Anonymous. I'm attempting to get in contact with the poster of that information so I can get detailed instructions and see if I can verify the results.

Well I spoke to the user, and he said that all you need to do it turn down the speech in the game in order to run it off (maybe a game restart is required?). At any case, I was able to play for much longer, but the game still crashed. It still sucks, but it's an improvement.

I sended a support request to GOG.com about this, and their solution actually worked for me ( run as administrator ). But instead of right-clicking the shortcut and click " run as administrator " I went to properties and selected it there, don't know if that makes such a big difference ...
I didn't have to reinstall the game, and for those who want to know, my OS is vista

I've had great success with forcing directx9 by adding -dx9 to the solon heritage shortcut.

Hey I just started playing this. I've tried the solutions listed here (besides the one involving turning off the sound since I'm playing Vector Prime and Star Wars just wouldn't be Star Wars without sound in space) but none of them have worked. :( I'm using Windows 7 pro 64 bit and have an integrated sound card if it matters, but I guess it seems like no one has managed to get it to actually work in any way besides playing it on XP... :( I suppose I'll just have to install it as a seperate OS or something.

BBalazs has found a fix for the sound bug, which fixes it hopefully for all mods, versions, etc. And it doesn't require any scripting or turning the sound off.

More about it will be posted soon on ModDB!

Hello!
Sorry for my English i'm French...
I've solved the problem on my system (Vista 32) by forcing DirectX 9.
In Haegemonia properties add -dx9 behind the target:
C:\...\Hegemonia\Hgm.exe -dx9
And run the game in XP2 compatibility as Administrator.
You can enhance ingame resolution too by adding -w 1680 -h 1050 behind the target (1680x1050 is an example you can choose any size you want).
C:\...\Hegemonia\Hgm.exe -dx9 -w 1680 -h 1050
No more crashes for me. :)
I hope it could help you!

Well I have cut it down to the FX sound files. I only have the crash happen when I play the game with the FX sound on. Voice and Music work fine and i have no prob runing the game for hours with them on. As soon as i turn FX volume up a little I crash not long after. Hope this helps run that pesky bug down and some one can kill it.