search autocomplete works on directory theme when admin only, help !

I installed the search autocomplete plugin (and tried 10 or more others). I can get autocomplete to work fine as long as I’m logged in as admin. If logged in as any other role or not logged in at all, the autocomplete doesn’t work.

Does anyone know if there is a javascript / jquery bit of code causing this to not work ? is there some sort of authentication I’m missing?

I appreciate any help, Thanks,