Are you using Power CMS, the Solution pack?
Or Power CNS Builder, the extension?
these are 2 separate products.
the Power CMS Builder Extension is an MXP File that you download and install into Dreamweaver.
the Power CMS Solution pack is a zip file containing a collection of php files that upload to your server.
The solution pack does not create a menu item in Dreamweaver.
to use the solution pack, you log into the power CMS Admin section that is created on your web site to create content areas, for each content are you create, there will be a link to Developer Notes. the developer notes will give you php code to add to your pages where the content area should be displayed.