The firewall seems to have run out of resources. It's a 1.7Ghz machine with 256MB RAM and seems to be darn sluggish. I would have never thought that most firewalls would even use up anywhere near this amount of resources but then, not everything is designed the same way.
Could someone confirm that the above error message has to do with the machine not being powerful enough? I was not able to grab any stats before I rebooted unfortunately.