Users Settings Error and unable to switch users

Binary package hint: gnome-panel

I have recently installed Ubuntu and created two users.

First problem was with switching between users and ended up with a blank screen and unable to get any response.
Seems to work ok when logging into either user individually from startup.

Trying to checkout the user setup through System/Admin/Users and Groups and get a blank window that doesn't respond.

tried "gksudo strace users-admin" and found lots of possible errors, some of the text as follows
    access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
    read(3, 0xbfe49a6c, 32) = -1 EAGAIN (Resource temporarily unavailable)

ProblemType: Bug
Architecture: i386
Date: Sun May 13 13:21:18 2007
DistroRelease: Ubuntu 7.04
ExecutablePath: /usr/bin/gnome-panel
Package: gnome-panel 1:2.18.1-0ubuntu3.1
PackageArchitecture: i386
ProcCmdline: gnome-panel --sm-client-id default1
ProcCwd: /home/curtis
ProcEnviron:
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=en_NZ.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-panel
Uname: Linux curtis-desktop 2.6.20-15-generic #2 SMP Sun Apr 15 07:36:31 UTC 2007 i686 GNU/Linux