This same problem happened with my wife's 6-DISC CD changer in our 2003 Windstar. Ford wants $300+ to replace/repair it. We've never used CDs with label stickers or odd-thickness CDs in it. In fact, we've never had anything other than store-bought audio CDs in it. It still has 6 in it at this very moment that we can't get out.
I was told by the nice service advisor at our local Ford Dealer that this is a common problem with these and that one can get it repaired at a local car audio repair place for a lot less.
Also, I found a couple of places advertising on ebay a repair service for this very problem. These places don't like you attempting to remove the CDs or repair it yourself though, so beware.
I'll get this repaired as soon as I can and maybe check back with the results. | 
