Your packs are missing track 18; they have a duplicate of track 17 instead.
Well, that's embarassing. I'll re-rip the missing track and re-upload the packs. EDIT: The new packs are uploaded now!
This CD was a mixed data/audio CD. The data portion contained Lemmings and Oh No! More Lemmings (it didn't need to be installed; even if it was, you had to have the CD in.) The audio is used for the levels. I could never get the audio working when I was younger, playing it on Windows 95 and 98, but it works with DOSBox perfectly.
EDIT: I found a folder named DOXVIEW on the disc, which contained a copy of the instruction manual. The DOX file was mostly plain-text but contained references to some PCX images. I manually converted it to HTML/PNG and you can read it here:
http://www.lakora.us/lemmings/dox/Also, here's what the disc looks like, in case you're curious. The silver part actually isn't colored at all - just the same color as the disc itself.