it's really strange. If you follow the avwizard wizard, at the end you will be able to use the UI that you select during the wizard.
Take a look to this file : /etc/pluto.conf
Verify if this keys are correct or not :
UseVideoWizard = 1
PlutoVersion = 22.214.171.124.09092222331
FirstBoot = false
AVWizardOverride = 0
AVWizardDone = 1
DesktopActivated = 1
DVDKeysCache = /home/.dvdcss
With this keys I have the UI working well.
Also you can check this file /var/log/mce-installer-20090829_170721.log
Keep the correct file with the correct timestamp, that is related to your installation.
For me is the first time to hear about this kind of situation post a new installation from scratch