Do you have another hard drive connected to your Mac?
If yes, then that’s why, Canon and Lacie is the worst possible combination (more due to Canon)
because of their proprietory FireWire.
My FCP doesn’t recognise (slightly different problem from yours) my Canon GL2,
when my 2 Lacie drives are daisy chained.
Try to connect your Lacie HDs to your Mac via different FireWire ports
(i.e. one to FW 800 and other to FW 400).
To completely solve the issue, install another FW in an empty PCI slot,
because no matter how many FW ports you’ve got – they all run through
the same FW card.
Mick