Most likely, your disc has some damages/bad-press as dialysis mentioned.
(As my understanding, stand alone DVD players accept/ignore certain level of read errors. So, playable with one stand-alone player does not mean there is no damage/error on the disc.) You may need some cleaning / repairing the disc, especially if scratches are visible.
Though if your disc is old release, DVD Decrypter may be able to rip your disc. After installation, Tools>Setting>options, increase Read Error Retries or check ?Ignore Read Errors? under I/O tab. (I do not know other ripping software that a user can set this.)
(edit: I have no idea why "DVD decrypter" links to AnyDVD in this message...)
"DVD Decrypter may be able to rip your disc. After installation, Tools>Setting>options, increase Read Error Retries or check ?Ignore Read Errors? under I/O tab. (I do not know other ripping software that a user can set this.)"
milly8- God bless you!!!- 65 Tries that's what I called Dogged Persistence !!!!! - personality traits like that Can make you either A valued & trusted Friend or a Feared and hated enemy !!! I'm betting on the friendly side Though !!! Cheers My friend