WD MyBook 1TB won't connect via Firewire

Hello,
I recently bought a 1tb Western Digital MyBook Home Edition external HDD, which supports connecting via USB, Firewire and eSATA.
I've connected it to my computer via USB, and it worked flawlessly.
However, when I try connecting it via Firewire, I generally get the connected hardware sound, then nothing happens for a while, and then it might eventually turn up in my computer as "Local Disk: H" or something, but when I try opening it, I get an I/O error. When I open up device manager, it's under disk drives as: "WD My Book IEEE 1394 SBP2 Device", with a yellow exclamation mark next to it. In properties it says something like "This device is unable to start" or something similar, and the location is "LUN 0".
I'd really appreciate it if you could help me get it working with Firewire, as the only reason I bought it was for the Firewire connection.