Could be something to do with your keyboard. Some (cheaper) keyboards don't allow certain keys to be pressed in combination due to the way they're wired. Have you tried re-assigning the keys to something different such as WASD or the numpad?
That is definitely a problem with the keyboard. You'll have to map the keys to something else for playing. Use the Test Input screen to see what combination of keys will actually work with your keyboard.
< cybik> til Kyzentun fixes bugs for breakfast
< maxvg1> shakesoda: then why do i still play lol
<@shakesoda> because you're an ITG player. And thus, a masochist
<@shakesoda> Kyzentun: I think you might need to put down the meshes for a bit