Assuming you have MI 1 on CD, then you need to tell ScummVM where to go to play the redbook audio on the disc. You have to specify a command line option in a DOS prompt window, so:
1. Launch a command prompt. Start > Accessories > Command prompt.
2. Type cd\scummvm, then enter (hopefully you know a little DOS
Also, that path only works if that's where your directory for scummvm exists. You will have to browse elsewhere if you installed your Scumm elsewhere.
3. type scumm vm --help You'll see a list of all the commands you can input.
4. the command "--cdrom=NUM" tells it where to look for your CD audio, with NUM being the number assigned to the CD-ROM drive you're playing off of. (Make sure this CD drive can play back music- like from a music CD, first) If you don't know what number to use start with 1 and go up from there.
In my instance to launch Monkey 1 with CD music on Scumm version 0.9:
C:\ScummVM\scummvm --cdrom=1 -pc:\monkey1
(the last part of that is a path for where monkey 1 resides on my computer.)
I hope that works for you. Don't forget to check in the ScummVM help file and their website also for more.