This question has been answered by charless. See the first response.
[[!mxfb? ]]
[[!mxfb? ]]
[[mxfb?&formid=`1`]]
[[!mxfb?&formid=`1`]]
<html><head> <title>404 Not Found</title> </head><body> <h1>Not Found</h1> <p>The requested URL /connectors/resource/index.php was not found on this server.</p> <hr> <address>Apache Server at demo.xxx.com Port 80</address> </body></html>
<html><head> <title>404 Not Found</title> </head><body> <h1>Not Found</h1> <p>The requested URL /connectors/security/user.php was not found on this server.</p> <hr> <address>Apache Server at demo.xxx.com Port 80</address> </body></html>