Memorex Media especially DL Media is absolute garbage and should be avoided. Memorex DL Media is manufacture by CMC Magnetics Taiwan and CMC Magnetics Taiwan has a well-documented history of producing inferior poor quality problematic DVD Media. If you doubt that assessment concerning Memorex DL Media just perform a Forum Search on the topic.
At this date/time the only DL Media that produces quality error free results is Verbatim DL MKM001/MKM003 Mitsubishi Kagaku Media. Experimenting with any other DL Media other than Verbatim DVD DL MKM001/MKM003 Mitsubishi Kagaku Media will produce unacceptable results.
I echo Forum Member coolcolors suggestion concerning ensuring that your DVD Burner has the most current up to date Firmware that is available. Suggest visiting the CD Freaks DVD Burner Forum for assistance with DVD Burner Firmware ->