Crash when open one particular .mscz file

It never happened since i use this softvare, but at this time i wanted to create parts and while i was selecting the instruments, Musescore crashed. Since then it always crashes when I try to open this particular file. I would need it right now, but i would be grateful if you could help me later as well. It would be suck to rewrite it.
I use MuseScore 1.2 by the way, becouse my Mac is 10.6.8 and i cannot update it.