Had a lot of issues myself before I started running VLC exclusively [videolan.org]. It’s a great lightweight player that supports every codec natively. If you’re not yet using it, I suggest giving it a run to determine if this is software or hardware related and begin a process of elimination. Worst-case, may be a flaky drive.
My TR3 DVD has performed well enough, it’s not been excessively used, but it’s never exhibited issue when on long flights et al.