i just try UltraVNC 1.0.1 with SC and it works great without encryption.
When i use encryption plug-in, there is this error :
[img=http://img456.imageshack.us/img456/5416/error1ax.gif]
So, this is like i made :
i use this in my "helpdesk.txt" file :
-plugin -connect 82.66.74.30:5500 -noregistry
i generate a "rc4.key" file with UltraVNCViewer (config button) and copy it for my zip file.
i launch UltraVNCViewer : vncviewer.exe -listen -dsmplugin MSRC4Plugin.dsm
i made the "exe" file, here : http://sc.uvnc.com/index.php?section=19 with the "UltraVncSC based on REL1.00 " option.
The connection failed with the same error

I try the "MSRC4Plugin.dsm" file with the 1.0.1 version and also the "MSRC4Plugin.dsm" file that is here : http://ultravnc.sourceforge.net/addons/singleclick.html (bottom page)
These twos to generate the key and to launch UltraVNCViewer.
I think that the problem is realy the version of the "MSRC4Plugin.dsm" to use...
Can anyone have an idea, and help me !
Matthieu.