Fix Wordpress Menu

I am having problems with the menu on the following website ([login to view URL]). I need an experienced Wordpress PHP developer to take a look at this site and make the necessary code changes to allow the user to hide pages from the menu. We have tried using the "Hidden Pages" plugin which has worked for us on several other websites but we can't get it to work on this site. There must be some issue with how the initial designer coded the Wordpress Theme. I have attached the theme code as a zip file below to give service providers to check to see if this is a problem they can fix.