This was originally filed upstream as http://bugzilla.gnome.org/show_bug.cgi?id=359605 and 2.16.2 has a possible fix, which we should test and possibly pull in.
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux major release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Major release. This request is not yet committed for inclusion.
Included in gnome-screensaver-2.16.1-4.el5
A package has been built which should help the problem described in this bug report. This report is therefore being closed with a resolution of CURRENTRELEASE. You may reopen this bug report if the solution does not work for you.