SELECT...FROM...WHERE NOT EXISTS... doesn't work

[Nik Korfhage]

Hello,
I cannot recognize the syntax error in this query:

SELECT topic_id, FROM `phpbb_topics`
WHERE
NOT EXISTS (SELECT * FROM `phpbb_posts`,
WHERE phpbb_posts.post_id = phpbb_topics.topic_last_post_id)

returns:
#1064 - 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 'FROM `phpbb_topics`
WHERE
NOT EXISTS (SELECT * FROM `phpbb_

Can anyone help me? Thanks.