Thin Client Manager and x11vnc on Clients

[M Rathburn]

Edubuntu 8.04 running LTSP v5 i386
Thin clients are diskless workstations PXE2.1 i386

Installed the Thin Client Manager software.  Followed instructions for
setting up the thin client environment here:
https://wiki.edubuntu.org/InstallX11VncOnLtspClients

Rebooted everything including the server.

When running Thin Client Manager, the program can 'see' the thin clients
connected (left hand column).  Can 'see' the processes being run, etc.
However, the Viewer portion can't see the thin clients.  Says 'Unavailable
(install x11vnc on the client)'.  I've done that per the above reference.
What have I missed?

How do I check the thin client to make certain that x11vnc is installed and
running?

More info: Able to successfully connect to the thin client via Remote
Desktop Viewer.  Also able to view the thin client session in the program
iTalc.

Thanks.