Final Cut Video is Pixelated

Please take a look at the picture below.

http://www.flickr.com/photos/66212682@N02/6032786238/

The video isn't pixelated in FCP7 without a MB Look applied. But when I put a preset Look on it (coolish alternate) and hit finished it appears pixelated and jerky even after rendering on the timeline. If I take it off the video appears normal again....please help. I am using a MacPro
2 x 2.26 Ghz Quad Core Intel Xeon - ATI Radeon HD 4870

It's driving me crazy!

found the answer on another thread

http://forums.creativecow.net/readpost/138/855938