Did you rip the entire DVD, or just certain files?
Did you then use DVD Shrink to create a DVD folder with new files in it, then drag all of those new files into the VIDEO_TS folder that Nero brings up? It sounds like some of the files needed to burn the DVD are missing from the folder. Nero is looking at the IFO file (if it's there) and not finding something that the IFO is saying is supposed to be there. I had that problem with Shrek 2 when it leaked onto the net, and to make a working DVD I used a program called IFO EDIT to get rid of all the extra crap in the MANY IFOs, and just make ONE IFO file for the 4 or 5 VOB files that contained the movie. So, I lost all the menus and animated crap when you put the DVD in, but the actual movie works perfect.
You can download it here:
http://www.doom9.org/software.htm
It's under VOB tools on the bottom of the page. The program was hard as fuck to figure out, but it can fix your problem.
EDIT: IFO EDIT GUIDE
http://www.doom9.org/mpg/ifoedit-basic.htm