Last of Us Technical Issues

Has anyone been having major technical issues with The Last of Us. I have recently gotten stuck galloping in the sky with my horse during the horse riding segment and now my saved game won't load. I have an older "fat" PS3 and I have restored the file system but it still didn't fix the issues.

I actually rented the game from a Redbox kiosk and the disks I've been getting have no scratches or smudges. Does anyone know if Redbox gets a cheaper copy of the game than the retail version?

This is the first PS3 game that I've had any issues with? I'm leaning towards the game itself being the culprit?