Updated to 5.2, tried the plugin, then turned off Maintenance Mode and then disabled the plugin. I went back to my site and got Maintenance Mode. Went to log in and get fatal error.
Fatal error: Call to undefined function wpf_current_time_fixed() in /data/21/2/44/93/2044093/user/2239141/htdocs/blog1/wp-content/plugins/mingle-forum/wpf.class.php on line 1605
I will back in the morning.