I got this error in the server log: call_user_func(xPortal_Install::uninstallCode) [<a href='function.call-user-func'>function.call-user-func</a>]: First argument is expected to be a valid callback library/XenForo/DataWriter/AddOn.php:148 xPortal still appears in Options but the addon is uninstalled. Any idea how can I get rid of this problem? I have re-uploaded library/ files of XF Beta 6 but it hasn't worked. Now when I press F5 to reload in the forum index, sometimes I get: The following error occurred The server responded with an error. The error message is in the console. Update: I don't know if the problem is due to the plugin.