Okay, i've been getting a lot of help with this problem from a lot of different people - and it comes down to one thing now, so I thought I'd just start over with a simplified version.

$_DOCUMENT_ROOT is set to /home/username/web/

$_DOCUMENT_ROOT returns null.

I have two (nearly) identical servers going. It returns properly on one, and not the other.

Can someone offer a suggestion? Also - is it acceptable to have a "/" at the end of the path as shown above? Cause that's the only difference I can see when I run phpinfo.

thank you.

See your other thread. Did you do the following or anything similar:
$DOCUMENT_ROOT = $_SERVER['DOCUMENT_ROOT'];