I assume you burned a movie, since you tried to play it in your DVD player.
What did you burn on it ?
A DVD Rip ?
A ConvertXtoDVD converted file ?
Did you need NTSC and you have a PAL video ?
Did you burn it as a VideoDVD or DATA ?
The media needs to be CLOSED (Finalised) to be able to play in a DVD Player.
Have the latest firmware on your Plextor-760a ? (v1.06)