Pro 3 blocked applications from loading and caused permission issues

I chose the Advanced Firewall with Defense+ during installation of Pro 3.

Having run through all the initial set-up processes, I discovered that my applications would not load because the relevant file associations were no longer present.

I uninstalled Pro 3 and then reinstalled the basic firewall. The file association issue disappeared. Can anyone explain this phenomenon?

Also, it is worth mentioning that, with the first install, my computer locked up and I could not even restart in the normal manner (I’m running Vista Home). I received a message telling me that I did not have the relevant permission! The only way to reboot was to power off the computer.