A little old post I know, but everything I search for including a PHP file in xenforo is outdated, if that matters or not.
Anyways, I've followed the instructions here and after some trial and error I finally got the page showing without errors (mostly due to file paths that I overlooked), but, it's not showing the contents of the php file it's pointing to. Which is located at /donate/donate.php.
The main content PHP file is a donation script that requires other PHP files for mysql connection and config.
The include file path is the absolute path to the donate.php so I know it's pointing to it.
Callback is XenForo_Pages_Test :: includeFile
All that's showing is the title "Donations" then the footer.
I'm tired and probably overlooking something, but thought I'd post and see if someone can help me somehow by tomorrow.