superfish menu not working

I just installed the Danland theme, and the superfish menu doesn't work for me. in the docs, it says to setup the "Primary Menu", but all I see is the "Main menu". I've created two links, the second as a child of the parent, moved the 'Main Menu" into the Superfish block, but nothing happens. Am I missing something? do i need to install a module to make this work? Appreciate any help.

Doug