Prassi, Nero 5.5.8.2 -- What don't they like?

I've noticed that Prassi PrimoDVD and Nero 5.5.8.2 don't like some IfoEdit edited movies. (Prassi seems really picky; it wouldn't even take a ripped single-layer movie with no changes.) Nero 5.5.8.2 took a split movie and a regenerated IFO from IfoEdit -- but not one with selective edits. As has been noted, 5.5.8.0 is less picky, but I'm not sure that's a good thing. So what exactly don't these programs like? I'm guessing it's something that some standalones don't like either. Maybe if IfoEdit could be gotten to generate output that Prassi likes, then standalone compatibility would go up. See also from bluespot:

Nero also has the option to not check your video_ts folder (sort of..) To do this, I don't choose DVD video. Instead, I pick DVD ROM UDF/ISO. Then I drag my reauthored video_ts from my hdd into the root of the new DVD window in Nero, and burn. I've created countless perfectly working copies with this method.

I saw those options, but I was afraid to use them. I didn't know if Primo/Nero would still physically lay out the IFO, BUP, and VOB files on the disc correctly. So far the only reliable method (for my standalones) is to use the ImgTool (DVD Wise engine).

Well, like I said, I use Nero that way constantly with no problems. I did that dvd image thing for a bit (using ifoedit to create the image file) but one day it didnt work right for me, then it worked well for a couple more, then it didnt work again, so i scrapped that method since for me it was unreliable. Plus, Nero wont let me burn an image to a DVD. Is there a way to do that? If i select "burn image" I only get offered cdr/cdrw drives to burn to, I can't select my dvdr.