error message

Hello,

I am new at drupal; i am creating a new website and I have this error message showing on one of the menus I created:

user warning: Unknown column 'u.signature_format' in 'field list' query: SELECT c.cid as cid, c.pid, c.nid, c.subject, c.comment, c.format, c.timestamp, c.name, c.mail, c.homepage, u.uid, u.name AS registered_name, u.signature, u.signature_format, u.picture, u.data, c.thread, c.status FROM drup_comments c INNER JOIN drup_users u ON c.uid = u.uid WHERE c.nid = 22 AND c.status = 0 ORDER BY c.thread DESC LIMIT 0, 50 in /home2/sbyrcorg/public_html/club/modules/comment/comment.module on line 992.

thanks for your help,