Okay Let me go down your list
this is correct
$data_dir = "http://www.couch-tomatoe.cc/photopost/data/"; //URL of your photo dir where those jpeg stored (with / at end)
<?
require ("/home/scroungr/public_html/ubbthreads/photopost.inc.php");
//
// Featured Photos Code
// Follow down to End Feature Photos Code
//
$Globals['pp_db_prefix'] = "w3t_"; <<<<THIS DOES NOT SEEM RIGHT
You would set this to whatever prefix your photopost install has if any. If your tables read settings photos etc etc without a prefix this is set to blank. This is not set to your forums prefix which you have it set to unless you made the prefix to photopost this.
and the last line as I stated in the instructions. On most hosts expecially when using the sidebar you need to fill in the database for threads here since you will get errors if you do not have this line in there. DATABASE is set to your forums database.