Protools won't allow my playback drive today!!!

[Aqualove_]

Any ideas people...?
Yesterday everything worked fine and I was using my portable firewire drive/volume for playback of a Protools session, no prob. Today- a different story. I attempt to open the same session and receive error messages -
1. "The original disk allocation for this session cannot be used. One or more drives could not be found or are invalid for this session. As a result, disk allocation has been modified. Would you like to verify the new disk allocation?" (click yes- it will not allow me to change the disk allocation back to it's original location on the removable drive) Click no and receive this error message:
2. "12 audio files are on volumes unsuitable for playback. Would you like to copy them to a suitable volume?"

HELP! How come it worked yesterday, then trainwrecked today?!

Any comments welcome on this subject.
GRAZIE MILLE!
Tim

[DigiTechSupt]

More information is required - computer model, OS version, Pro Tools version, type of drive being used, etc.

Have you tried all the steps in the OS X Setup and General Troubleshooting thread yet?

[Aqualove_]

Using G5 desktop Dual 1.8 GHz 1 GB ram
OSX 10.3.9
Protools version 6.8.1

The drive I'm using is an Other World Computing Neptune firewire drive 160 GB capacity
here are the specs:

OXFORD IDE Device LUN 0:

Capacity: 153.38 GB
Manufacturer: Oxford Semiconductor Ltd.
Model: OXFORD IDE Device LUN 0
Removable Media: No
Detachable Drive: Yes
BSD Name: disk3
OS9 Drivers: No
Speed: 400 Mb/sec Speed
Unit Spec Id: 24734
Firmware Revision: V34O
Unit Software Version: 10483

1Daimond (<--drive name):

Capacity: 153.38 GB
Available: 55.87 GB
Writable: Yes
File System: HFS+
BSD Name: disk3s3
Mount Point: /Volumes/1Daimond

Thanks for your time and help!
Tim

[Aqualove_]

1 more thing...
MBOX 2 interface
cheers!