Photoshop CS3 - "Save for Web & Devices" Colour Loss

I use Photoshop CS3 on my Macbook, and when trying to save a file using "Save for Web & Devices" for some reason, there is a significant colour loss. When looking at the original file in Photoshop, and then looking at the optimized AND original file within the "Save for..." option, the colour difference is huge. It's not a rich, and it gets much paler.
So I'm not sure what the problem considering that the original working file looks just fine, but then when i go into saving it.... the original and optimized file look pale and not as rich!
I've been fiddling with settings and not getting any results that way, so I'm not sure what is going on.
Does anyone else using CS3 have this problem? Know how to fix it? Anything? I would really appreciate it!