Question

When i hook up the firewire in the back of my board all inputs are cut. Everything works before I hookup the wire and after I take the wire out. I am running firmware 1.50a and build 190.

Answer 1

Are you hot plugging firewire?  That is VERY MUCH not recommended.  It will eventually burn out your ports or cable.

Connect everything with the system shut down.  Power the mixer first, then power the computer.

That should get you going.