It can sometimes be challenging to get your local server up and running. Once your server is setup you basically just need to load the db, set the values in the globals file and start testing the pages.
You say that you have php pages working in your testing server, where do these pages reside? If you are getting 404 errors for the pages you are trying to preview from within Dreamweaver then you most likely do not have the URL prefix setup correctly for your testing server. How have you defined the testing server and what values are you using there? Also when you are able to view php pages successfully on your testing server what is the URL for those pages?
Once you have all the details matched up correctly you should be able to user the PowerStore without issue. Please post back and include specifics about what step in the process you are on, what you have done successfully already, and what you current result is. With this info we should be able to point you in the right direction.
