I have been backing up my movies for years without problems using dvd fab decrypter and DVD Shrink combo. The last five movies I backed up are full of compressions problems which pause/reset the disc when playing.
What gives, this was such a reliable combo I'm now pulling out my hair.
When was the last time you updated the firmware on your burner? Also, check and make sure your DMA is enabled on your drives and that they have not slipped into PIO mode, here is a guide
The majority of members do not think to highly of Memorex media, but if you have been using it with success and like it then stick with it. But Verbatim is better and there is no difference in price when you buy it on sale.
Obviously there are issues if I cannot successfully backup a disc with it. I have followed the .pdf and with the exception of the second drive everything else was the same. I did unistall the second drive to check if it makes a difference. Always can system restore if it adversely effects settings. Also will pick up some Verbatim discs today.
Bermuda has limited resources so hopefully the local store has these in stock.
You can also check to see if there are any Sony or Maxell discs (made in Japan) which are usually are Taiyo Yudens which are the Cadillacs)As in you name "can" the Memorexes.