The problem is the path to the Connections/localhost.php file.
Look at the full address to the power CMS files. if the address to login is:
and the page you are adding powerCMS to is at:
the developer notes path needs to be adjusted to:
<?php include "powerCMS/Connections/localhost.php"; ?>
<?php include "powerCMS/WA_CMS/WA_CMS.php"; ?>
if you are having trouble with getting the path correct, please post a link to your pwerCMS login page and the page you are trying to add powerCMS to so when can help.