Well, this is the error message that I get when I tried to run Desktop Sharing in KDE Control Center (Internet & Network):
¨There was an error loading the module¨
The dialog screen has an option for details that say:
Library files for ¨libkcm_krfb.la¨ not found in paths
(still in details option)
Possible reasons:
An error occurred during your last KDE upgrade leaving an orphaned control module
You have old third party modules lying around
Check these points carefully and try to remove the module mentioned in the error message. If this fails, consider contacting your distributor or packager.
I have no firewall installed.