[chillyjim]

From the command line of the "new firewall" enter the command "fw unloadlocal" and see if that brings back your conectivity.

As for the rest, are you running a single system (FW and Management on the same box) or a distributed system?

As jobroco said, this type of problem tends to be do to anti-spoofing and can be fixed in the topology tab of the firewall object. To get started, you might want to disable the anti-spoofing on the interface you are connecting too untill you get everything else set.