I have one XF 1.3.3 installation that's working perfectly with Facebook integration, and now I'm setting up another one, but in this case XF is in a directory (specifically http://lightpull.org/l ). When using the "Test Facebook Integration" tool on this second installation I keep getting: Not Found The requested URL /admin.php was not found on this server. I've tried putting the site url into facebook with and without the /l , and other than that all the settings are identical to the one that works, in both the FB app and in XF (other than different app IDs obviously). Also, I do have an admin.php file in the /l folder. Any ideas?