Thanks for your report. This seems to be bug 48732, and occurs due to strange model names on certain disks. This is fixed in dapper-updates, so you can work around it by upgrading all packages with 'ubiquity' in their names on the running live CD before starting the installer.
-- error while reading file system https://launchpad.net/bugs/57407 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
