update-manager crashed with RuntimeError in <module>()

[dwp0980]

Binary package hint: update-manager

pc left on for several days. all sorts crashed when I tried to update.

ProblemType: Crash
Architecture: i386
DistroRelease: Ubuntu 8.10
ExecutablePath: /usr/bin/update-manager
InterpreterPath: /usr/bin/python2.5
NonfreeKernelModules: nvidia
Package: update-manager 1:0.93.18
PackageArchitecture: all
ProcAttrCurrent: unconfined
ProcCmdline: /usr/bin/python2.5 /usr/bin/update-manager
ProcEnviron:
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
PythonArgs: ['/usr/bin/update-manager']
SourcePackage: update-manager
Title: update-manager crashed with RuntimeError in <module>()
Traceback:
 Traceback (most recent call last):
   File "/usr/bin/update-manager", line 44, in <module>
     gtk.init_check()
 RuntimeError: could not open display
Uname: Linux 2.6.27-4-generic i686
UserGroups: adm admin audio cdrom dialout dip floppy fuse lpadmin plugdev video