I'm having trouble with /viewport

[Dynatron768]

Whenever I change my viewport at all the game screen just freezes up. My interface works fine, I can move my character and cast spells and such, but the actual game world part of the screen is stuck. When I go into full screen and back out the screen is just all black except for the interface. The only way to fix it is to log out and delete the UI .ini file for the character. Just logging out and then back in isn't enough.

I've tried the default interface, I've completely reinstalled titanium with the latest p99 patch files and nothing extra, and I've reinstalled my video card drivers. Nothing seems to work. Any ideas?

https://i.imgur.com/YkCtStJ.png