Event+ error when creating new event

Hi,

I have just installed Events+ plugin on our new site and it's giving me an error whenever I create a new event.
The site has wordpress 3.5.1, bbpress 2.2.4 and membership plugin installed.

The error I am getting is as following:

Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'portfolio_custom_columns' was given in /home/learntot/public_html/dev.learntotune.com/wp-includes/plugin.php on line 406

Please help.
Thanks and Regards,
David