Try this: In libs/ubbthreads.inc.php Replace This:
Code
if (isset($_SERVER['PATH_INFO']) && !$PATH_INFO) {
$PATH_INFO = $_SERVER['PATH_INFO'];
} // end if
With This:
Code
if (isset($_SERVER['PATH_INFO']) && !$PATH_INFO) {
$PATH_INFO = $_SERVER['PATH_INFO'];
} // end if
elseif (isset($_SERVER['ORIG_PATH_INFO']) && !$PATH_INFO) {
$PATH_INFO = $_SERVER['ORIG_PATH_INFO'];
} // end if