I can´t record/playback to/from my firewire drive

[CharlyRivera]

PLEASE HELP!!!!
I´ve been using 002 on G5 with an Altum firewire drive since a year and a half ago and suddenly my system reports this problem out of nowhere:
Can´t create a new session on my external drive, and this message pops up:

"Session must be on a record audio volume"

Can´t playback any other session from the same drive. While session is loading I´m asked to check disk allocation and then all audio files apparently have been moved to the Macintosh HD. I cancel this and when session is loaded this message appears:

"Audio files are on volumes unsuitable for playback. Would you like to copy them to a suitable volume?"

When a try lo allocate files the only suitable volume is Macintosh HD, but, as you might guess, this means another kind of problems.

I reformatted and re-partitioned the external drive and I reinstalled Pro Tools and none of this seemed to work it out.
Am I missing something???