its prabably bad media. DVD-r is the most compliant format and has been around the longest. I could see if it would play - and not + but not the other way around. Stay away from "fly by night" brands. Look around there's alot of information about media on this site. I use Verbatim. It also could be the firmware like what was already said.
i have been using phillips brand. it seems to be working fine . plus i also use memorex i tried phillips dvd-rs and got the problem, but also been using phillips dvd + r and they are fine.
Some companys contract with different venders to make there disk. It could be that even though they both are Phillips brand thay could be made by two different companys
