Hey There.
I just bought DK2. I loved it... especially the Music.
But i just dont have ingame Music.
Found nothing about it in the Forum yet.

Greetz

When you move the slider for music in the in-game Sound menu (Esc => Sound), there should be music playing as long as you keep the mouse button pressed to validate the volume setting. Check if this works. I've turned it down as I play my own music, but as far as I can remember, there isn't always music playing in the background.

I had the same issue (no music) in both DK1 (KeeperFX) and DK2 a month ago or so and I just reinstalled the games and the music was back in both games. I saw that some of the sound files were lost and the other ones were corrupted (changed names, different sizes). They looked like:

JFJGF93H5393R3________
D93UJT5J39GJ39________
RFJ3JT0J30J0J03________

Strange things happens sometimes.