Re: problems importing into shake

I assume you are bringing in a quicktime clip? Shake can be a bit picky about codecs, you can get some random stuff happen from time to time depending on what codec you're rendering out with.
To fault find i'd suggest just connecting a file in node with your source footage to a file out node (so we're eliminating any image processing that might be going on, such as colour corrections). If the footage looks wrong when you view it in shake (compared to what is was in your editing software), then I'd try exporting it as a different codec (animation codec or a tif sequence).
If the footage looks fine in the viewer while you're working with it in Shake, then I'd try rendering out as an animation codec quicktime (for 8bit you will get no quality loss on the image), if this doesn't work (i.e. you still get compression weirdness), try rendering out to a TIF image sequence.

Shake itself will not degrade an image without you connecting nodes in the tree thats job is to mess with the image (...something to note is if you lift the levels of footage that was acquired in a compressed format such as DV, HDV, etc, you will get blockiness and other nasty artifacts revealed). I think the issue will be a quicktime codec one, but let us know if you have no joy with my suggestions.

Goodluck,

andrew

:-)