002 rack disconnects with mac mini after 5 minutes

[ourafilmes]

Hello.
Untill yesterday I was a happy man.
Suddently while listening to a track in a flash player in Safari, 002R turns MUTE on and stops audio.
From there on I can´t work with any program.
It says problems with Firewire bus or firewire connections but I didn´t touch anything!
Not even with Pro Tools I can´t work.
Yesterday night I had a 2 minute render to do and I just did it after more than 20 trys. It was a miracle to do it. Always stopping.
This was in PTLE 7.1.1. Today I updated to PTLE7.3 but It still stops.
I did a mac mini firmware update and it keeps stopping all the time. More than 10 minutes with 002R always on is a miracle...
Until yesterday it worked perfectly.
Should this be a 002R problem or a mac mini firewire problem? I tried with a Hard disc - 002R - Video Converter chain and it doesn´t work like last week!!!
I need to work (small projects but they need to be done)
If I turn off the firewire cable and let the 002 on its own it still mutes after a while!!!!
What Should I do?

Thanks

Miguel
Portugal