Screensaver exits account! Please help!

[Alex Damiani <alex80it libero it>]

Hi!
I have a proble with my screensaver. I am running redHat Linux 7, and in
Gnome, if I don't do anything for a few mins, the screensaver starts,
but instead of showing me what I had chosen, it exits my account and
asks to log in again. If I try to access the GNOME configuration tool,
and I click on the "Screensaver" icon on the left hand side, it still
exits my account without letting me change the settings.
Could you tell me what's wrong, and, most of all, how to fix it?
Is there a place I can go to look for a configuration file for the
screensaver, that I can reset, or something?

thanks in advance,
                                    Alex