Integrating with Moodle (problem)

[eluser]Jay Jennings[/eluser]
I'm using Moodle as a shell for some of my online tools -- creating a "course" that links to an external page (also on the same server as Moodle).

But now I'm trying to switch over to CodeIgniter for my PHP development (I love it!) and am having some problems. Specifically, for the external PHP pages to use the Moodle vars, I need to include this line at the top of my pages:

include("/path/to/Moodle/config.php");

That allows my pages to make sure the user is logged in to Moodle, etc. But when I try to include that line in my controller file, I get this error:

A PHP Error was encountered
Severity: User Notice
Message: Fatal: $CFG->wwwroot is not configured! Exiting.
Filename: lib/setup.php
Line Number: 88

I believe that's coming from Moodle, not CI, but I'm kind of lost as to why it's happening and what to do to fix it.

Have I given anyone enough information to point me in the right direction?

Thanks!

Jay Jennings