Hi. Frankly, I don't know if this is a CloneDVD issue, and I'm uncertain as to which forum this topic really belongs in (it could be the Plextor one).
I have a Plextor PX716A FW1.06, and I use AnyDVD 126.96.36.199 and CloneDVD 3.0. I copied two movies (a total of three Video DVDs), and it turned out I can only watch them on my PC. I tried both an "average" DVD player and a Playstation 2: it both cases, the discs could not be read. It doesn't seem like this is a media issue to me - at least the PS2 would've struggled, given noises, before giving up. I'm compelled to believe this is either an application software (AnyDVD & CloneDVD) issue or a hardware one (either a physical characteristic or a firmware issue).
I've only very recently (try last Saturday :P) started burning DVDs, so I haven't actually experimented with lots of DVD-R of different brands. I hope someone here can shed some light into this matter. Thanks.