Running some applications causes log off

 I upgraded to 10.10 a week or so ago and this causes Skype, Virtual Box and when my cursor goes to the indicator section of the top bar to log me out. From lspci my graphics card is

         VGA compatible controller: nVidia Corporation G86 [Quadro NVS 290] (rev a1)

I am using the recommended nVidia additional drivers.

         $ date > VirtualBox.crash && VirtualBox 2>> VirtualBox.crash && tail /var/log/syslog >> VirtualBox.crash

         $ more VirtualBox.crash
           Fri Oct 29 12:52:26 BST 2010
           Xlib: extension "RANDR" missing on display ":0.0".
           <unknown>: Fatal IO error 11 (Resource temporarily unavailable) on X server :0.0.

When grepping the logs I get....

        /var/log/daemon.log:Oct 29 12:52:37 gdm-session-worker[2544]: GLib-GObject-CRITICAL: g_value_get_boolean: assertion `G_VALUE_HOLDS_BOOLEAN (value)' failed

       /var/log/syslog:Oct 29 12:52:41 NetworkManager[923]: <error> [1288353161.663126] [nm-manager.c:1317] user_proxy_init(): could not init user settings proxy: (3) Could not get owner of name 'org.freedesktop.NetworkManagerUserSettings': no such name

I did have to install python-libproxy_0.3.1-1ubuntu1_all.deb separately when upgrading as the company firewall blocks any address that has proxy in (!**??)...

Unfortunately this has caused me to have to duel boot into windows for testing and using a remote desktop through IE, I really don't want to keep doing this