Pidgin: gaim crash

i am trying to use portable gaim from school. i start it, it connects to all the protocols, but after a little bit it just closes, without saying anything at all. it just closes. i've tried to use it both from the pen and from the hard disk, it has the same problem. from the computer at home, though, it works perfectly from the pen.

any ideas?

(i've tried both 1.50 and 2.0, same problem)