issue with plug in - wp-classified

Hi I tried installing the wp-classified advert plug in but get the following error message at the top of every page

Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'WP_Classified::handle_pagetitle' was given in /home/worldha1/public_html/wp-includes/plugin.php on line 166

Any ideas?

Many thanks

Toby
http://www.worldham.org