Applications that require root privileges freeze

[Giorgos Kounenis <kounenis@gmail.com>]

I did the default installation of Debian 6.06, I log in Gnome as the
created user and every time I try to run an application which requires
root privileges, eg. Synaptic, Users and Groups, etc the application
freezes. I need to run xkill and kill it.

Any ideas what might be going on?

Thanks,
Giorgos