I have spent the past week fighting with a bug in CentOS 6. It does not recognize my on-board NIC and thus does not install some networking components. Unless I plug in a second NIC. Then networking is installed and BOTH NICs work(?) so my memory on this Ubuntu bug may be a little fuzzy...
According to the bug I filed against 11.10 https://bugs.launchpad.net/ubuntu/+source/debian-installer/+bug/799515 The problem existed in 11.10 server alpha 1 but not in the alternate CD 11.10 alpha 1 (pardon the typo in the other bug report). 11.10 alpha 2 works fine in both the server and the alternate CD.
I don't remember if it was in 11.04 as I have not played much with that version.
Is this a kernel bug or an installer bug?
I wonder if installing from a USB connected drive would work? When I need to take a break from this CentOS issue I may give that a try.