The plugin textdomain is not loaded properly and thus leaves the plugin un-able to be translated. I've implemented a fix, so anyone trying to use another language with this plugin can do so.
In bpfb.php in lines 32-52 many variables are declared to make the proper textdomain and plugin folder locations, however it doesn't work in the latest version of WordPress. The simplest fix I found is to bypass the variable declarations and just change line 53 to be in the proper format like so :
load_plugin_textdomain( 'bpfb', false, dirname( plugin_basename( __FILE__ ) ) . '/languages/' );
Please update your plugin to reflect proper WordPress textdomain declarations. Thank you.