I ran into a popular problem with trying to restore files backed up with NERO without access to the *.nbi file. I had previously ran a file system backup to 8 DVD's and then my system crashed. Upon attempting to restore, I was unable to access the *nbi file on the last DVD. All other files on every DVD was readable. I found that I was only able to restore one individual file at a time which was extremely painful especially with 2000 photos.
Through this newsgroup and others, I saw references to a command line restore but no one was having much success and it was not working for me either. Then I realized it was all in the syntax of the restore command. More specifically, a semi-colon.
So, you back up your files to DVD. On each DVD, the top-level backup folder is called something like 2007####_####_yourname. Assuming that your DVD is labeled drive E on your computer, the process is...
At a command prompt, change to the "\program files\Nero\Nero 7\Nero Backitup" (or wherever you installed NERO) directory, then type...
Backitup.exe /NEW:Restore /PATHLIST:"E:\2*;"
The 2* is just a wildcard variable referencing the name of your backup folder. Also, note the semi-colon inside of the " at the end of the statement. Once you run that command, the GUI should launch and you will be presented with the restore application. At this point, you will not be able to select or do anything. Be patient and watch your DVD drive. Hopefully it is flashing like crazy as the app scans the DVD and attempts to load the backup contents. It may take 15+ minutes before the contents are loaded. Once its complete, you should be presented with the contents of the DVD and you can restore at will.
A couple items of note...The default restore point was actually back to the E:\ drive. You can select to restore to an alternate point on the hard drive. Also, folders retained their 8.3 format but files restored with full name. I hope this helps. I spent many hours fighting this beast so I thought I would share the solution. If any of this is unclear, post back and I will go into more detail.