Comment 22 for bug 757720

I can also confirm that this is indeed a problem with the final 11-04 AMD64-image.

I posted details here at first: https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/730209/comments/38

IMHO this should be a critical bug. As the alternate cd fails after the partitioning step when run from usb (probaly because it uses on of the partitions as a temp dir) and the netinstall image takes a good 90 minutes to complete an install (not to mention it is very beginner-unfriendly), the install functionality should really just work off of the live cd.