I think the Monkey Island 1 problem is that it's the cd-version, it should have cd music, so must be something wrong with my files.
Can you play the Monkey Island audio tracks you created in any media player?
I have Monkey Island (from my own CD) and the audio tracks work fine, I saved them as 128kbps stereo mp3s - they have to be named in a specific fashion:
From the Scummvm readme:
>7.8.0) Using MP3 files for CD audio:
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Use LAME or some other MP3 encoder to rip the cd audio tracks to files.
Name the files track1.mp3 track2.mp3 etc.
so, all lower case and no spaces,
track1.mp3
track2.mp3
and so on - not track01 or track 01.
You'll also need to have the community codec pack installed if you haven't already.
Should work then.