frend plugin not workong

i am running wordpress 3.1
getting this error when i go to friend request and the action table is empty.
Fatal error: Call to undefined function get_blog_option() in /hermes/bosweb/web089/b899/ipw.arashliv/public_html/arashlive/arashlive/wp-content/plugins/friends/friends.php on line 601
plz advice