[leonsio]

which vbulletin do you use?
in which folder is server.php located?
if you use other folder than /soap you must edit a patch to you forum at the top of the server.php

vbrand functions is in the functions.php, which is loaded by the constructor of the class
so that i think it can not be found

look at the CWD constant

define('CWD', '../' ); <-- i think you must change this

example to: ./ if you running server.php in the forumroot