How far into boot are you getting before it fails? Have you installed Ubuntu to hard disk (if so, did the live CD boot alright?) or are you just trying and failing to boot to the CD?
Also I don't know what hwinfo is. It sounds like maybe a BSD program. What you want to use on Ubuntu is:
And the modprobe commands won't necessarily give any output unless an error occurs. Try running with the --verbose option. You may in fact be at the right command prompt and just don't realize it. If that's the case, then running the command:
and rebooting would probably solve the problem altogether.
echo 'blacklist 8139cp' >> /etc/modprobe.d/blacklist
If not, if you do have Ubuntu on your hard drive, another solution would be to either remove the network card or disable it in BIOS, if possible, and then boot into Ubuntu normally.
A third approach is to mount the Ubuntu file system under Windows or BSD and move or delete the 8139cp module. It should be located at /lib/modules/[your kernel version]/kernel/drivers/net/. Keep in mind that if you have more than one kernel installed, there will be a copy of 8139cp.ko for each kernel.
If you're trying to boot to the live CD but are unable because of this problem, you could edit the ISO file to remove 8139cp.ko. I think that Archive Manager in Ubuntu can do that, and I know of a few Windows programs that can as well.
As for the problem being solved in Hardy: there's a good chance that it is. Do you know the exact chipset of your card or its lspci entry? If so, some quick Googling would probably answer the question.