Problem Firewire 400 on snow leopard

Hello greetings.

actuamente snow leopard and I have recently bought an audio interface (saffire pro focustire 40) which I can not use a connection through Firewire400, Mac tells me that a device is connected but it does not work. I knew I could be looking for my firewire problem but I could not fix it.

I hope someone can help me with this please.

blessing