I recently saw your message and it is exactly what happened to me too.

Installed to HD correctly, and when the KDE login screen comes up, I login, but it makes a loop and comes right back to the logon.

Then I tried changing the logon type from DEFAULT to KDE3 I believe... and believe it or not... it worked perfectly!

Now if I could just get the RealTek 8100B onboard eth0 to load, I would be in business. It seems to choke on loading full duplex mode, and cannot then receive a DHCP signal from the router.