Roxio Toast 12 Titanium - Avoid

This sounds more like a hardware problem than a software problem.
When did you last use a lens cleaner on your drive? It builds up gunk even when unused.
Toast used to be extremely tolerant of drive errors, it just took longer when it found them.

 

Use an app called burn. It's free. You won't get a pretty menu, but it's fast at converting. Problem with toast is that it only uses one core to convert while burn uses ffmpeg, which uses all your cores.