After installing the Security Update 2009-006 (via Software Update) for 10.5.8, none of my external FW disks will mount on the desktop!

I have OWC FW drives (one on the 400 bus and one on the 800 FW bus) running on a Mac Pro, dual 2.7 ghz PPC G5.

This problem is not solved by: Disconnecting, reconnecting the drives or restarting the computer.

System Profiler (Firewire) states "Unable to list any firewire devices" although they are properly connected and powered.

Both FW drives mount easily when connected to my MacBook Pro, so the issue is not with the externals or cables.

Any suggestions? I need these drives for backup and large file access, and am in a world of hurt right now.

Thanks in advance for any replies.