Duplicating Pages Plug-ins won’t work.

I am having an issue with my new theme, because I can not duplicate pages. I have tried the “Duplicate Page” plug-in that you recommend and it does not work. I have also tried another duplication plug-in. One plug-in would always duplicate the same. page, over an over again and not the one I was asking it to. The other would only duplicate the navigation bar. Didn’t work. I think I might have a problem with my theme? What to do??