I just tested mIRC v6.35 under Wine and it crashed the moment I tried to play a .mid file. It was able to play a .wav file once or twice and then crashed. It was able to play an .mp3 file without any issues, as far as I could tell.
mIRC v7.17 and v6.35 use exactly the same method to play sound files, other than a minor change to the way .wav files are played to get around the crash bug in Wine.
I ran a debug version of mIRC v7.17 under Wine and it did not play .mid or .mp3 files either, and did not return any errors. I have not taken a look at the Wine source code, however at a guess it looks like Wine may not be handling the calls for playing .mid and .mp3 files from Unicode applications. It may be that there is a stub that simply returns "success" in this case.
That's about as far as I can go to cater for Wine - the next step would be to download the Wine source code and to analyze it to see how I can work around these issues, which just isn't practical I'm afraid.
