You are getting this error because of the connection to your db, it is telling you that you do not have access to the db with the username you have provided without any password. If you want to edit locally you will need to ensure that the connection is pointing to your local MySQL db and that you have the correct username and password entered. Did you install this locally or on the live server? You may need to go through the install process locally to get the site setup for local editing.
As far as making the products list horizontally across the results page here is a thread where some other users have done the same thing. This is not a supported feature of the PowerStore though and will require customizing the css and other properties on the page.
showthread.php?t=11885
