Starmall_Shipment_Model
s
It is prepending Mage because it is one of the core directories.. In my server, I see /var/www/app/code/core/Mage/ as a navigable path.
Put your standalone scripts in your mage base dir, and use the following code at the "beginning"
Hopefully this will be enough to get your magento up and running, then you can figure out why the paths aren't working the way you expect.