If you've just copied and pasted an example of your webspace path relative to the server, then the 'username' bit is probably supposed to be changed to your own webspace username:
PHP Code:
chdir('/home/USERNAME - CHANGE/public_html/forumtest');
This is most likely the problem because the PHP parser can't find what you want it to find - meaning it's either not there, or you've specified the wrong path.