MySql erros on server error log.

Hi,

I have hundreds of this error on my error_log file:

[26-Sep-2011 09:17:07] WordPress database error You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE meta_key = 'site_name' AND site_id = 0' at line 1 for query SELECT meta_value FROM WHERE meta_key = 'site_name' AND site_id = 0 made by require, require_once, require_once, require_once, do_action, call_user_func_array, automessage->poll_new_users, automessage->add_user_message, Auto_User->send_message

Is this error from automessage plugin ?

How to fix this ? Why is it caused ?
Please help.

Thank you.