package sugar-session-0.88 (not installed) failed to install/upgrade: trying to overwrite '/usr/share/xsessions/sugar.desktop', which is also in package sugar-session-0.90 0.90.3-1

[aurelius]

When I try to boot into the sugar desktop the screen goes blank and then returns to the login screen.

ProblemType: Package
DistroRelease: Ubuntu 12.04
Package: sugar-session-0.88 (not installed)
ProcVersionSignature: Ubuntu 3.2.0-30.48-generic 3.2.27
Uname: Linux 3.2.0-30-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.0.1-0ubuntu13
Architecture: amd64
Date: Thu Sep 27 00:25:00 2012
DpkgTerminalLog:
 Unpacking sugar-session-0.88 (from .../sugar-session-0.88_0.88.1-5ubuntu1_all.deb) ...
 dpkg: error processing /var/cache/apt/archives/sugar-session-0.88_0.88.1-5ubuntu1_all.deb (--unpack):
  trying to overwrite '/usr/share/xsessions/sugar.desktop', which is also in package sugar-session-0.90 0.90.3-1
DuplicateSignature:
 Unpacking sugar-session-0.88 (from .../sugar-session-0.88_0.88.1-5ubuntu1_all.deb) ...
 dpkg: error processing /var/cache/apt/archives/sugar-session-0.88_0.88.1-5ubuntu1_all.deb (--unpack):
  trying to overwrite '/usr/share/xsessions/sugar.desktop', which is also in package sugar-session-0.90 0.90.3-1
ErrorMessage: trying to overwrite '/usr/share/xsessions/sugar.desktop', which is also in package sugar-session-0.90 0.90.3-1
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
SourcePackage: sugar-0.88
Title: package sugar-session-0.88 (not installed) failed to install/upgrade: trying to overwrite '/usr/share/xsessions/sugar.desktop', which is also in package sugar-session-0.90 0.90.3-1
UpgradeStatus: No upgrade log present (probably fresh install)