buddypress-sliding-login-panel.1.2 not working

i have problem wan i install this Plugin and i refresh home page
i see nothing
i used child “thematic theme ” i think this make different !
if i post
<? if(function_exists(updateHeader)) updateHeader(); ?>
on top i get this
Fatal error: Call to undefined function bp_has_message_threads() in E:\xampp\htdocs\logo\wp-content\plugins\buddypress-sliding-login-panel\update-content.php on line 21
i test all position and nothing
pleas any idea 🙁

http://wordpress.org/extend/plugins/buddypress-sliding-login-panel/