Warning: call_user_func_array() [function.call-user-func-array]: - Any idea how to get rid of this e

I have a fresh Wordpress installation (3.3.1) and the Classifieds plugin activated. This error is showing up: Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'load_dirtdivas_js' was given in /home/dirtdiva/classifieds/wp-includes/plugin.php on line 405. When I activate the default Twenty Eleven 1.3 theme the error goes away, but when my custom theme is activated it shows up again. Any idea what may be causing this in my site?