When I got those errors, it meant it wasn't able to read the disc on that certain part of the disc (physical location btw). The only workaround that I found was to let it try again, which usually worked or take out the disc, give it a quick clean with a microfiber cloth and give it another shot.
If it continued, then the disc has a scratch that makes it unusable for ripping. Unfortunately that means that you will need to buy another copy of that disc. It has happened to me before with a disc or two. The new disc ripped just fine.