PRO TOOLS shuts down right after recording!!!

[tendashi]

hi there,

i use pro tools le 8 with an 'mbox 2 factory' and i am having nerve-wracking problems to get it going today as it keeps shutting down when recording a mixdown to a stereo track.
it does record but when i hit stop all the volume-level-displays briefly freeze and it shuts down, repeatedly saying 'pro tools shut down unexpectedly' etc...
i have worked on the same session just 2 days ago and everything was fine. i think i did an itunes update in between though, could that have caused any trouble?
occasionally it even shuts down when just saving a session, btw.
i've been through numerous forum threads by now, but couldn't find any satisfying solutions.

please help me out asap as i have to finish some mixes urgently.

thank you!!