Fatal Error _email_address_unsafe() [add new users plugin]

Hi Aaron

Unfortunately when I execute Add New Users plugin
[WP 3.0 + BP 1252 not MU INSTALL] this error appears

Fatal error: Call to undefined function is_email_address_unsafe() in /home/ggsuse2/public_html/wp-content/plugins/add-new-users.php on line 362

How can I fix this?
All the best