I am having the same problems when trying to burn or play burned CDs through iTunes. Even when it looks as though it successfully burned a disc through iTunes, when I attempt to play a burned disc, the disc drive ejects the CD without explanation. And, that's only after it appears to successfully completed the burn process and preceded by anywhere from 3-10 failed burn attempts because it ejects every blank disc while iTunes gets hung up on it's original message "Please insert blank CD" twice and then quits the burn process requiring you to start over with the 3rd, 5th, etc. blank discs. This is the most recent problem in a long line of issues I've experienced with my iMac, which is only 6 months old and I will never purchase a Mac again. Every previous problem since purchasing my iMac posted as a question went without any answer or assistance from Apple and I'm gobsmacked by the lack of service or support.
Message was edited by: neofight77