last nero back-up disc problems

Recently I needed to wipe my C:/ drive. I had to buy a new external disc drive to do so, and it was the first time I use Nero when I used it's back-up function to back up My Documents.

Now, I am unable to decompress the last disc (it used 5 or 6 discs). The first ones were able to decompress, although the names weren't the same and there were one or two files missing.

I kind of need the files that were on the last disc though. Using 7-Zip or WinRar doesn't do it, and there seems to be no function on Nero at all to reinstall a back-up.

Can someone please help.