SoundLib 3.1 is BUGGED, if some of your users are using SoundLib 3.1, they will have to REPLACE with SoundLib 3.2 (available in the "Librairies&Headers" Folder or REMOVE it from the Extension Folder !
The bug happens ONLY when calling MADGetBestDriver function on PPC Macintosh with SoundManager 3.1. (GetSoundOutputInfo)
Actual version of SoundManager is 3.2.1 and is included in system 7.6. (2/1/97)