Download DVD Speedtest and post the transfer speed graphs of the DVD in question, using the I/O and NEC. Are you using 8X burn or 4X? Try a full burn with the NEC. Those Memorex DVDs are not very good in quality and often result in playback issues. The drive that burn the DVD will usually be able to read its own burn.
Try Made in Japan media from Fuji, TDK, Maxell, or Sony. I avoid ALL Memorex products.