LaCie d2 Hard Disk - problems

Hey, there, anybody who might have a suggestion. I upgraded a while back to Leopard. I had a LaCie d2 drive that worked just fine on my iMac. Today I tried to get it to mount and it won't even show up on the desktop.

However, I plugged the firewire into my laptop (that is still running Tiger) and it mounts fine, just like before.

The problem is that I need it to work on my iMac (Leopard) as that's the computer that has my Final Cut pro on it and the LaCie disk is where I'm keeping all my media...

Ideas? SHould I simply go to the LaCie disk and install whatever Silverlining Softward or SilverKeeper software?

Help? :-)

m