okay, I'm not sure about this but my best guess is that the midi tracks contain sysex info that is not stored in banks but as raw information in the track. try opening the midi files into something like cakewalk and check if there's any GM-mode sysex messages and program select messages. this might cause your inconvenience.
you could also check this by altering patches and see if they change once you start the song or once the part starts playing. this is a clear indication that the sequence contains any of the formentioned messages.
good luck and keep us informed about the results or progress.
Bas

[This message has been edited by Bungle (edited 11-21-2001).]