I recently purchased a Ford In-dash 6 disk CD changer to replace the standard radio in my '99 Ranger. I purchased it on e-bay. The unit installed in a snap, however, when I try to load a CD, I get a "CD ERROR" or "SLOTS FULL" message. When I press "CD", I get a "NO CD" message. I am contacting the person I purchased the unit from but was wondering if anyone might know a quick fix for my problem.