Is there anyway to pull the user's username to use outside the /forums/ directory

[dragonexpert]

You don't need to execute it from a template at all. I"m not too familiar with using the superglobal $_SESSION. Try using session_start() on the line after require_once. You can just use the $mybb->user object though for your needs most likely as it contains the uid, username, email, and other information about a user.