Nero data DVD problem

Hello, I am trying to use Nero 6.0 to backup various files on my HDD as I am planning on formatting. I have been using it for about six months, mostly burning DVD videos. I've hardly had a failed burn out of hundreds of DVD vids and numerous CDs. I can still burn a DVD video without a problem, but when I try to burn a full DVD-ROM (ISO) I keep having the same problem.. The burn begins without a problem, with buffer levels 90+ the whole time. The problem occurs when it gets to about 92% complete. The used buffer level reduces in the manner it does before lead out, but just as it's almost at 0 the program crashes and exits to windows. The disk initially appears unreadable (if I try to view the contents it tells me the disk is empty), but after rebooting the disk is viewable, but not all folders are readable. If I try to open them it freezes up for a few seconds and doesn't open. The files I am trying to backup consist of lots of very small files, some larger files, and many directories and subdirectories.. Anyone know what could be causing this problem?

Thanks, Ted