Great News. I found the solution. Apparently, the "caribou" rpm is incorrectly installed with the i686 version on x86-64 machines. So, after you get the "Oh no!" screen, hit ctrl-alt-f3 and proceed to logon. Then you become root and do the following:
rpm -e --nodeps caribou
yum install caribou
make sure you get the x86-64 version.
Then ctrl-alt-del and bingo it works.
I found this info here: