Adding WinSCP to Windows Vista search path

I am trying to add WinSCP to the search path of a windows Vista computer. When I go to to Preferences, Integration, and then click, "Add WinSCP to search path" Vista blocks and denies the registry edit. Is there a way to get Vista to allow it, or a manual way to to add the registry values?

I do not have a Vista. In XP you would do that from "System" control panel applet