Hi,
I've resvolved my problem !
Here's the solution :
In the file lobbies.ascx in DesktopModules\CuteChatControls\, on the line containing the link to "Chat Admin", the URL is /DesktopModules/CuteSoft_Client/CuteChat/Admin, but the ~ is missing at the beginning. So the URL in the file is /DesktopModules/CuteSoft_Client/CuteChat/Admin and must be changed to ~/DesktopModules/CuteSoft_Client/CuteChat/Admin to work...
Tibo