AVI ??? AVI is a container format and not suitable for DVDs
That it doesn't make any sense (to me) to convert a DVD to an AVI then to an ISO to burn a new DVD
A Tip at first:
Next time you make an ISO, play it with
VLC first to see if it has sound/picture OK before you waste another blanc

As for your troubled Disc..the way I would go about that is this
First I try to rip the disc with
DVDShrink directly to ISO which then gets burned on a blanc.
If that rip fails I use
DVDFab (it's a trial) to rip the parts I want to Harddrive first and use then DVDShrink on that directory (it's faster that way compared to have DVDFab create the ISO)
Or you could as well use DVD Rebuilder Free.
Read HERE How that goes exactly
-DG