package gnome-session 2.32.1-0ubuntu20 failed to install/upgrade: trying to overwrite '/usr/share/gnome-session/sessions/ubuntu.session', which is also in package gnome-session-common 2.32.1-0ubuntu20

[marius]

Binary package hint: gnome-session

Occurred when trying to undo my install of Gnome 3 (which crashed after about 2 minutes).

ProblemType: Package
DistroRelease: Ubuntu 11.04
Package: gnome-session 2.32.1-0ubuntu20
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: fglrx
Architecture: i386
Date: Sun May 22 11:41:07 2011
DpkgTerminalLog:
 Preparing to replace gnome-session 2.32.1-0ubuntu20 (using .../gnome-session_3.0.1-0ubuntu1~build2_all.deb) ...
 Unpacking replacement gnome-session ...
 dpkg: error processing /var/cache/apt/archives/gnome-session_3.0.1-0ubuntu1~build2_all.deb (--unpack):
  trying to overwrite '/usr/share/gnome-session/sessions/ubuntu.session', which is also in package gnome-session-common 2.32.1-0ubuntu20
ErrorMessage: trying to overwrite '/usr/share/gnome-session/sessions/ubuntu.session', which is also in package gnome-session-common 2.32.1-0ubuntu20
PackageArchitecture: all
SourcePackage: gnome-session
Title: package gnome-session 2.32.1-0ubuntu20 failed to install/upgrade: trying to overwrite '/usr/share/gnome-session/sessions/ubuntu.session', which is also in package gnome-session-common 2.32.1-0ubuntu20
UpgradeStatus: Upgraded to natty on 2011-04-30 (21 days ago)