Newb in serious trouble with aliasing (I think)

Hi Everyone,

So we shot an artist's installation that is lit by, and relies heavily upon, videos projected everywhere. The projection was our only light source. The footage looks beautiful, except for these terrible lines caused by the projector's frequency. I think this might be what people refer to as aliasing, not too sure if it's exactly the same thing.

A slow shutter speed didn't help, so I have no other choice but to try fix it in post. Premiere's antialiasing filter didn't do anything.

This project is very important to me - please, please help me out.

(Oh, and we shot on a 550D)