Comment 1 for bug 52739

The kernel is having great difficulty reading from your CD. There's lots of stuff like this in the syslog:

Jul 12 08:48:23 ubuntu kernel: [ 1221.579471] SQUASHFS error: zlib_fs returned unexpected result 0xfffffffd
Jul 12 08:48:23 ubuntu kernel: [ 1221.581790] SQUASHFS error: Unable to read fragment cache block [b4031b]
Jul 12 08:48:23 ubuntu kernel: [ 1221.583073] SQUASHFS error: Unable to read page, block b4031b, size 38de

I'd suggest burning the CD at a lower speed and cleaning the CD drive lens with the sort of cleaning kit that you can get at electronics shops, then doing a CD integrity check from the boot menu before you next start the installer.