Firewire Failure, ext drive won't boot Options

[stratosfear]

dear friends,
i'm quite anxious about not being able to boot my firewire drive. Has anyone had a error message that reads " a disk attempting to mount as unknown has failed verification or has failed to mount. Please use disk utility to check the disk and correct any errors". The firewire has music i've been working 6 months on and I was trying to back the latest sessions up, and so i am treading very carefully with this problem.
I am running an mbox with 6.1 pro tools on a single 1.25 G4 using OS-X. Any remedies would be greatly appreciated. Thanks

[stratosfear]

thanks for yr guidance, i took the firewire over to a friends and it booted just fine and so i copied the whole thing into his newly installed internal HD AND all the data was still on the HD at the last studio I used, about 6 weeks ago...oh the universe can be kind, so all is well and my blood pressure is back at its usual geriatric level. i couldnt use the OS X disk utility as all the options were greyed out which was helpful! So the problem is in the gizzards of my prefs and will check out the apps and system set up itself. who knows I may even learn something. Thanks again and all the best.