Neither NX nor VNC can now connect to my system

[Mun]

Hi,

Particulars:
   Red Hat Enterprise Linux Client release 5.11 (Tikanga)

I have both NX and RealVNC (v.4.5) servers running on my RHEL virtual
machine.  Basically, I had RealVNC installed first, and then my company
switched to NX (a few years ago).

My system hadn't been rebooted in almost two months so I went ahead and
rebooted a couple of weeks ago.  Following the reboot, neither NX nor
VNC can now connect.

When I try with NX, the window just disappears before my display is even
shown.  When I try with VNC, I get the following error:

======================================================
Your session only lasted less than 10 seconds. If you have not logged
out yourself, this could mean that there is some installation problem or
that your may be out of diskspace. Try logging in with one of the
failsafe sessions to see if you can fix this problem.
======================================================

Note that I am using RealVNC in Service Mode via vnc.so .

I am guessing that one of the system updates that was applied in the
last two months must have had some ill-affect with NX and VNC; but so
far, I have not been able to figure out what may have changed.

I have searched the web and reached out to VNC, but so far I have not
stumbled upon a solution.

Any assistance would be *greatly* appreciated.

Regards,

-- 
Mun