Well I upgraded two systems from F10 to F11 using anaconda (booted the
DVD), run a yum update after that and it works just fine.
One of this systems have been running Fedora since FC4 and got updated
to F/FC N+1 using the same method and still works.
(FC4->FC5->FC6->F7->F8->F9->F10->F11)
Seems like your problem is that anaconda for some reasons crash on
your system, but with the infos you provided we can only speculate
what happened.