For all of those having trouble with Unreal Engine...

I tried for ages, Googling;

Mass Effect 2 can't move
Mass Effect 2 stuck
Unreal Tournament 3 can't move
Unreal Tournament 3 stuck

None of it found anything!

In desperation, I move to Epic's community fora, where I came across this post;

http://forums.epicgames.com/threads/920374-Keyboard-problem-in-UT3

Apparently Unreal Tournament 3 engine doesn't get on well with Synergy.

HTH

CMR