Database error

Any idea why I suddenly get this message when posting or when someone is posting a comment? The comment is posted but this error message is displayed. What would solve this?

WordPress database error: [Table ‘growmerc_wrdp1.wp_post2cat’ doesn’t exist]
SELECT cat_ID AS ID, MAX(post_modified) AS last_mod FROM wp_posts p LEFT JOIN wp_post2cat pc ON p.ID = pc.post_id LEFT JOIN wp_categories c ON pc.category_id = c.cat_ID WHERE post_status = ‘publish’ GROUP BY cat_ID