Gnome panel hangs after a click on System menu.

Description:
I am using Centos 5.3 over VNC.
VNC session hangs after a click on System menu in gnome panel. VNC session is back after killing gnome-panel process. Looks like gnome-panel hangs and VNC server waits forever for a response. After killing gnome-panel, system automatically starts new gnome-panel process and VNC session is enabled and works
correctly.
I do not know if this can be reproduced on a screen directly connected to the machine. (Do not have such screen).

Answer:
I'm sorry, the problem persisted after I rebooted and I could not edit my reply.

What I ultimately ended up doing was changing the default runlevel of CentOS in /etc/inittab to 3. This prevents X11 from starting on the local display, but vncserver will still start normally.

---Section of /etc/inittab below---
# Default runlevel. The runlevels used by RHS are:
# 0 - halt (Do NOT set initdefault to this)
# 1 - Single user mode
# 2 - Multiuser, without NFS (The same as 3, if you do not have networking)
# 3 - Full multiuser mode
# 4 - unused
# 5 - X11
# 6 - reboot (Do NOT set initdefault to this)
#
id:3:initdefault:

This works for me as I'm building a headless system, but I do not have a general fix. I've installed Fedora on the same machine and did not have this problem, it seems to be a bug in CentOS specifically.

Best,
Matthew Lyndaker