Do you have the original parts? What specifically is wrong?
My guess is that the brakes were made for Cannondale by another company but I have no idea who. Perhaps you can figure it out by comparing what you have to other brakes from the same era. The only disc brake bike I have is from around 2002 and it has Hayes brakes. I would have to go look at it but I don't think either the levers or the calipers look like yours.