just do a search for memorex on any of the subforums here. memorex is the cause of MOST newbie burning problems. their media is so unpredictable. they use whatevrr manufacturer is the cheapest, and the quality scans reflect that. if you bought 10 packs of memorex media, you'd probably have 10 different media codes on them.
my burners like imation branded MBIPG101R04 discs. have you gotten the picture yet that media codes matter and brands don't? imation uses more than one media code on their discs, and the ones other than MBI do not burn well in my burners. most, including MBI, Imation discs don't burn well on most peoples' burners.
best media to look for are Taiyo Yuden (TYG0X or YUDEN000T0X) and Verbatim (MCC00X and whatever the code is for the -R discs. don't kow off the top of my head)
verbatim media is reliable in that if you buy a pack of verbatim you know it will have a certain media code.
TYs can be purchased from www.rima.com by media code so you don't have to worry about guessing who repackages what.
@the original poster:
i never do conversions form wmv to dvd so I can't really give a suggestion on what program to use. Nero Vision express might be able to do it (i know it will encode .avi to dvd). maybe searching the videohelp.com guides for "wmv to dvd" will be your best bet.
as far as dvd format goes, dvds consist of 2 folders. the first, "AUDIO_TS" is empty 99.9% of the time. it has to be there for many programs to read it correctly though for structure purposes. the other folder is "VIDEO_TS" this folder contains .IFO, .BUP, and .VOB files. the .VOBs are basically mpeg-2 files with a special extension.
another important thing is to find out what dvd burner you have, go to the manufacturer's web site and download and install the latest firmware for your drive.