Ubuntu 12.10 doesn't complete the full installation from a burned ISO DVD disk. It seems to happen sometime after the retrieval of a language pack.I'm using an old Compaq nx9010 laptop. I used the check disk feature with Ubuntu before the install, and I checked the hard drive through the laptop bios, and everything checked out OK. I choose the update while installing option as well as without before installing, with the complete erase for both, with password required option, but nothing works.
I read a post not long ago where a guy was having the same problem you describe, so he turned off his router when it came to that part, Ubuntu gave up downloading the language packs since it had no network connection, the install completed, and he finished the updates afterward from inside his freshly installed Ubuntu. He said it worked for him.