Thanks guys for the input … I will test the firewall again without the Wireless device and hope it will not panic anymore or whatever happened. The CPU might be te culprit too, it doesn't have a fan since it's an embedded one ... But it's in a cool enough environment that it shouldn't be a problem, guess I'll be monitoring that one as well.
The strange thing is that it happened only the next day, while before it worked without a problem, but that's the name of the game isn't it.
Thanks again.