Maybe your bit rates are too high? In general, most players do well with burned media when video bit rates are 7 MBps or less.
Another thing to look at is burning speed. The lowest burning speed will provide the fewest amount of burn errors.
Finally, consider the media you are burning to. Best quality media is manufactured by Taiyo Yuden, Verbatim, and others. Go to videohelp.com and look at the compatibility matrices for different brands of DVD media.