UT3 doesn't love me the way it used to

[The_Keeper]

Kay well, hello UT3 community. I'm new here so... yay introductions.
Anyways, I have a strange problem play testing my levels.
I've been using UT3 Editor for awhile now but I neglected it for two weeks and came back to find it really messed up. I had to unhide brushes, reselect view modes, and now I'm finding more troubles just by trying to play test.

I'm not sure what's going on but suddenly, whenever I play test the controls go ultra sensitive so that when I run my character around the level, the camera goes nuts. I'm constantly finding my view going from the ground to the sky to the sides randomly with just the slightest touch of my mouse. The character isn't colliding with anything when this happens, he's just running across flat land so what's the deal? Why on earth is the camera jerking around so much?! I can't play test my work like this, it's giving me a headache ><

I just barely started building the basic greyblock for my level in additive mode before trying to play test it so I haven't the slightest idea of what I could've possibly done wrong.

If anyone has any ideas I'd super appreciate it, thanks.

[aCRaSSiCauDa]

You need to cover your level with either BSP or Skydome meshes or whatever... If you can see those blue wireframe you'll get the camera jerking like that when you click "Play from here".

[The_Keeper]

Thanks but...

The level was already covered by skydomes when I first tried to play test it.

I tried play testing the level on another computer at school and it worked fine, so I suspect the problem is either with my computer, the software or both. Should I try reinstalling?