Basically seeing problems accessing external drives, SuperDuper backup slow and prone to crashing causing kernel panics, Virusbarrier ditto. See my answer seems to be a known firewire driver fault in Snow Leopard which persists in 10.6.1.
copy IOFirewireSerialBusPRotocolTransport.kext your HD/System/Library/Extensions/
I can confirm now, that procedure above (my prev post) solved my issue. THANKS to Ken Marks! I used the Pacifist software (http://www.charlessoft.com/ ) and my Leopard Install disc to replace the IOFirewireSerialBusPRotocolTransport.kext file.
Instructions for Pacifist: 1.Download and install the sw from the website above. 2.Insert the Leopard (10.5) install disc and open Pacifist 3.Choose the 'Open Apple Install Discs' menu from the sw and let the program running 4.Once the program finished with the reading type OFirewireSerialBusPRotocolTransport.kext to the search field on the top right and hit enter 5.Right click on the file and choose 'install to other disc' and follow the onscreen informations. ( choose own HD and click on the 'install' button 6.Make sure that the ‘Use Administrator privileges’ ticked 7. Always click on overwrite the existing file. 8. Close all running applications on your machine and open DiskUtility and run the repair permissions.