Excluding forums in SQL query

[kgroneman]

I need some help with an SQL query. I'm trying to run a query to list the top posters but exclude some specific forums using vb_forumid, but it's not recognized. Here's the query BEFORE trying to exclude forums that works fine:

SELECT count(vb_post.postid) AS vb_postcount, vb_user.username
FROM vb_post AS vb_post
LEFT JOIN vb_user AS vb_user ON (vb_user.userid = vb_post.userid)
WHERE dateline > UNIX_TIMESTAMP(DATE_SUB(CURDATE(), INTERVAL 1 MONTH)) 
GROUP BY vb_post.userid
ORDER BY vb_postcount
DESC

When I add the forum IDs to exclude, I get the following error:

error number: 1054 
error desc: Unknown column 'vb_forumid' in 'where clause'

Here is the query that produces the error:

SELECT count(vb_post.postid) AS vb_postcount, vb_user.username
FROM vb_post AS vb_post
LEFT JOIN vb_user AS vb_user ON (vb_user.userid = vb_post.userid)
WHERE dateline > UNIX_TIMESTAMP(DATE_SUB(CURDATE(), INTERVAL 1 MONTH))
AND vb_forumid NOT IN  (10,588,589,591,592,593,594,595,597,599,601,608,609,641,644,645,646,647,649,650,652,654,671,689,737,739,740,741,782,783,1228,1229,1230,1231,1232,1233,1234,1235,1236,1237,1239,1240,1241,1242,1274,1275,1278,1279,1280,1289,1290,1292)
GROUP BY vb_post.userid
ORDER BY vb_postcount
DESC

I have another forum where I don't use the vb_ prefix (so it's just forumid, not vb_forumid) and the query runs fine so I don't get why this doesn't work on my prefixed forum. Help?