<< My guess is that it actually only reads cd-r's hence why once it rewrites it can't (laser) read the info anymore...
I think a problem could be the cd-r media you are running and how fast of a burn you are running...I think the faster the burn may result in less definition or depth of the burn and thus sensitive lasers may have troubles...
Example:
I can burn audio cd's at 4-8x and car player plays perfect...If I burn at 12x I get a lot of skipping or some playback issues. car player has anti-skip technology...Those same 12x cd-r's will play in my home cd player just fine, and my newer panasonic dvd player (rp-56) >>
Yes, player tolerance for border-line burns vaires greatly. My Pioneer CD changer will play ANYTHING, even things that can't be read by the burner that made them. But I have discmans that are very very picky.