First, I'd turn on the debug logging.
To change sound effects, right click, choose options, then the Sounds and music tab, then Event Sounds tab, the Game List Movement option is the one you want (very first item on the tab).
one minor catch is you can only use WAV files here. I'm using mala 1.7.4beta and it didn't want to play MP3's for any of the sound effects. Not sure why, since Mala can play MP3s in other places.