Tech Drive-In reports that there is currently a problem with GNOME Shell from GNOME3-Team PPA
Do not try to install GNOME Shell in Ubuntu 11.04 Natty Narwhal from GNOME3-Team PPA, at least for now. I was trying to do just and ended up with a completely unusable Ubuntu now. Even PPA-Purge was not able to fully recover my Ubuntu 11.04. I should have really read this warning before trying to install GNOME Shell in Ubuntu 11.04.DO NOT Install GNOME Shell in Ubuntu 11.04 Natty from GNOME3-Team PPA