I shouldn't imagine it's audio related, not if it happens both with CD and MP3 audio. The CD ROM activity isn't too surprising.

The screen darkening and brightening is the change of gamma value. It's TR's way to do a fade to black between scenes.

Do you see these problems both with and without VDos32?

Does it happen both with the OpenGL and Direct3D setting?

It only happens without vdos32.
I'm using direct3d. I haven't tried opengl yet. Tested so far:

1.42 with vdos32 - cdrom audio doesn't work, but mp3 does.

1.42 without vdos32 - both cdrom audio and mp3 work, game hangs on level change.

1.41 - without vdos32 - game doesn't hang on level change, but occasionally hangs up (very rare).

Result 1 probably not surprising. Use of VDos32 avoids all the Windows DOS emulation.

The difference between 1.41 and 1.42 I don't understand. Are you sure you are using Direct3D in both cases. The default for v1.41 was OpenGL.

1.42 fails in either direct3d or opengl mode, usually screen goes very dark.

1.41 fails only in direct3d mode. screen doesn't go dark, but after using task manager to terminate glide server, logging off shows TOMB.EXE still running.

I just browsed the forum for the first time in a while. If your still having the problem, I read this and remembered I had the same problem awhile back. I was told to download a preconfigured file and run it. It loads the correct files to run Tomb RAider. The file was named "TrAndUbForGlidos". This fixed my problem. Ask for this file.