Before you can upload and use the PowerStore or PowerCMS files, there are a few edits that need to be made to the WA_Globals/WA_Globals.php file and the Connections/localhost.php file. These edits are necassary to gather inforemation that is unique to your server.
In the Connections/localhost.php file you must specify the address for you MySQL Server, the username and password to connect and the database that you have added the necessary tables to.
Please refer to the Getting Started guides for Power Store on Power CMS for instructions on what must be done to get them running, The getting started guides are available in the Getting Started Section of the Support pages for those products:
For the error you are getting, see "How to update the database connection file" section: