I am no whizz on this stuff but I have had much the same thing as you, one thing that did get me for a while was that the laptop I use just wouldn't do anything with Phillips C/D's or DVD's, changed to Verbalin disc's (Spelling) and no problems at all, why Phillips have no idea.
The other thing I got was that while one laptop would transfer almost everything to disc, this new one did not, and found out it was the way in which the format my photos were being taken, the format JPEG etc, once I caught onto this I downloaded a piece from the internet which changed the format for anything, and everything worked.
One other thing which you might have forgot to do, I did, was to format them at the end of the recording, it generally ask's you if you want to play them on other media devices, one way to find out is to see if they will play back on the original computer you recorded them on, if they do then it seems a good bet they haven't been formatted correctly.
Hope something I have said helps you, It beats me though.