Plumax enclosure problem


I have plumax enclosure with both usb2 and firewire. It has pl3507C inside, and I update it with most recent firmware. The enclosure works fine through usb (I dont have usb2 ports), but the enclosure are not detected through firewire port. Any thoughts?

I have a dell inspiron 8100, the enclosure is connected to the laptop through a 6 pin to 4 pin firewire cable (inspiron has a 4 pin firewire port)