"I am using a brand new Mbox Mini and firewire." what firewire? The Mbox mini is USB
. Pretty sure you need 8.0.5 at the very least to go with LION. Its possible(I'm no Mac expert) that you need PT9. Follow the compatibility Grid link at the top of this page and look for the grid that shows which version of PT works on each version of OSX(and blame Apple for constantly changing stuff)