The patched version fixed it, now it's working fine on both machines. Thanks very much for the help!

I'm having problems getting Lemmings 2 to work properly. It lets me play the first level of each tribe, but when I beat it and choose to go to the next level, it just puts me back at the main menu. Saving the game doesn't work either.

I've tried it on computers running Vista and XP (both with Dosbox) and had the same issue.