To narrow down your problem even more, I would suggest trying to copy another, different DVD and see if the problem persists. If the problem consistently occurs at a specific point, the problem could be a bad speed shift by your DVD burner. DVD burners use a CLV (Constant Linear Velocity) write strategy- that is, they burn first a section at 4x, then at 6x, and finally, at 8x (for 8x media). When these upshifts occur, many people see a dramatic increase in detected errors, which could choke a playback device into submission.
If your Lite-On is a DVD burner, you can go to the Lite-On section of this forum and download K-Probe: a small, free utility that will analyze the error levels of your burnt DVDs. K-Probe will also tell you the media code of your blanks (which is not always consistent with the labeled brand of the media. Armed with that info, you can go to the DVD media test area of this forum and search for peoples’ experiences with the same media.