Invalid VNC server error specified

I recently migrated to ultra vnc from winvnc. I uninstalled winvnc and deleted the installed directory, after that I restarted the computer. Later I have installed ultra vnc. Now I can use the viewer to load vnc but when I try to save the connection and later on I try to open the connection through file that I have created its giving me the error. I have uninstalled and reinstalled the beta and stable versions but still I am getting the same error. After installation it is showing all the histories of previous connections. Even though it is a fresh installation. Maybe due to something in registry not cleared properly?

Invalid VNC server specified.
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