For detailed step-by-step instructions on how to recover an unfinalized DVD with ISObuster, read this link:
Another alternative that sometimes works is using Nero, a software suite that comes free with nearly every DVD drive sold for computers. Instructions for recovering with Nero can be found at this link:
Note two issues with ISObuster:
1. The free trial version can and does take FOREVER to do anything. Depending how badly the disc is damaged or corrupted, it is not unusual for it to spend literally days jerking around with the disc to finish its work. I once let it continue for three days before stopping it for fear it would kill my DVD drive in the process. People tend to recommend ISObuster as some sort of magic bullet, but its a pain to use and success is highly dependent on having a DVD drive with superb reading skills (most aren't that great). The specific damage to a particular disc is another important factor. So in your case, it may or may not actually be "stuck in a loop." Try it again tonight before you go to sleep, and let it run overnight for 6-8 hours. If it is still stuck at 2% in the morning, and hasn't gotten to at least 10%, you have a seriously bad corrupted sector that it can't ignore and gets stuck on. It probably won't work then, although there are various settings you can change that might allow it to skip that part and insert a patch over that sector.
2. The free trial version of ISObuster is often utterly useless. Depending on where/when you download it and what mood the developer is in that week, it might be a completely crippled barely functional demo. The most common complaint is that it won't actually recover anything: it gets stuck in a loop, or it won't allow saving the recovered files. While this is frustrating, you can sort of understand the developer's problem: most people don't turn to ISObuster until they need to recover a priceless damaged disc, something that usually occurs just once or twice in their lifetime. If the free trial version of ISObuster actually worked, nobody would ever pay for it: they'd recover their one disc for free and then forget about it. So most trial versions of ISObuster are crippled in some way, and won't work their magic until you pay for a license key. Whether this is worth it, only you can decide, but its a blind decision because you won't really know
if ISObuster can truly help until after you pay for it. You could try downloading the free trial from multiple sources,and eventually one might prove more functional than the others. There are some reports of success using the free trial, so a few of them must work (or those users found a way to trick it into thinking it was paid for).