I had TRAOD on cd. It worked fine and the 3D was amazing )nVision). But when I went from the level where you meet the skeleton warrior and you drop down through the metal grate come around a corner to a new level it comes up with an error message 'Insert disc 1' I tried copying all the cds contents to the game folders with no luck so I decided to buy it through GOG. Its even worse now!
1. I cannot save a game.
2. No 3D whatsoever.
3 I remap my keyboard and when I start again it is back to default.
4. When I exit I get a message from Windows The game encountered an error and needs to close. Even though I just ended the game.
I have 8.1 pro 64 but as I said it worked perfectly from the discs.

I have tried installing to C:/Gog C:/program files C:/program files X86 and also on my other hard drive with no luck.

I don't know about the 3D stuff but the other problems (saving game and prefs) seems like a permissions problem. Have you tried running the game as admin? (Right click on game's shortcut or exe file, choose properties, go to compatibility tab, check the box). Also, if the game is running in Win98 compatibility mod, you can uncheck it.