Making use of the bbcodeparse() function externally

[TWTCommish]

Hmmm, something's wrong. I started getting errors, so I tried to use chdir() to fix them. Here's what I'm using now. I have these two lines:

chdir("/usr/home/web/path/to/forums");
require("/usr/home/web/path/to/forums/global.php");

And then, I do this:

$comments = bbcodeparse2($comments,"1","1","1","1");

I get this error:

Fatal error: Call to a member function on a non-object in /usr/home/web/path/to/forums/admin/functions.php on line 75

Any idea what's wrong? Thanks for your help either way!