plug ins

When I have finished posting to my blog , if i try to save or save to edit later, I get the below message after each posting. I dont know what it means, but I have very few plugins on my site, I wondered if it had something to do with that. it seemed to start after I activated a feedburner plug in.
Can anyone please read this message and tell me what I need to do, Do I need a different template, will that help?
thank you so much,Ena

WordPress database error: [Table ‘organicg_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

Warning: Cannot modify header information – headers already sent by (output started at /home/organicg/public_html/wp-includes/wp-db.php:160) in /home/organicg/public_html/wp-includes/pluggable.php on line 391