It works now, Thanks.
To recap I added to line 1 the following code in the file where I placed the Developer note:
<?php require_once('PStore4/Connections/PowerStoreConnection.php'); ?>
<?php require_once( "PStore4/webassist/cms/cms.php" ); ?>
<?php require_once('PStore4/webassist/framework/library.php'); ?>
The PStore4 is in the code because that is the subfolder my Power Store is in.