Umm that is based off the server, so no you cannot be removed, and is probably a global message EVERYONE gets.
Another thing you can do is contact the master user of the account, other than that I'm not sure if it can be removed unless by him.
Doesn't matter if he was testing hacks, doesn't matter if your clan destroyed itself, doesn't matter if it was three years ago...
It was used to hack and that's the end of it, your responsible for your own key, and your own computer.
FYI, might wanna keep your story straight, since it's changed quite a bit since your original post.
Most likely has to do with the upgrade, it ports the permissions and some permissions for added for some features. So you didn't have permission cause it didn't exist and now it does, etc etc... Sure MayDax can fix it fast.
Run your game in Compatibility mode, for Windows XP SP2.
If that doesn't work make sure Window's Firewall is off.
The cvars don't change cause you're on Windows 7....