Memorex can be darn near anything. I guess you could look in the media tests in the Blank Media forum to see what the +RW disks have been in the past, but as I said, Nero CD/DVD Speed has a Disc Info tab that would tell us the manufacturer id code. That Nero program is free—found here
Virtually everyone on this forum has a bias against Memorex to some degree, so your disks are suspect. Verbatim is probably the best choice in my opinion for +RW media.
Did you try using the ISO in ImgBurn yet?
I’m still not convinced you have a good image file, but maybe you’ll prove me wrong. I don’t use Avi2DVD myself, I have other tools for this, but looking at that guide, I believe you get a folder called DVD in the output as well. It should contain the Video_TS folder that you can use in any burning program capable of burning dvd video. Nero for example.