Blogs Database error in vBulletin 4.1.0

[DanWest]

I hope this is the right forum for this question. When I try to enable Blogs on the site I get the Invalid SQL error below. Strange thing is that if I'm logged in as Admin it seem to work, but any other user get this error. Any idea what might be causing this?

I don't have any modifications installed and all blog posts were imported from a Ning site. It has worked before but now I get this error:
Invalid SQL:

(
SELECT COUNT(*) AS total,
FROM_UNIXTIME(dateline - 10800, '%c-%e-%Y') AS period
FROM forum_blog AS blog

WHERE state IN('visible', 'moderation', 'deleted') AND dateline >= 1311465600 AND dateline < 1312889953
GROUP BY period
) UNION (
SELECT COUNT(*) AS total,
FROM_UNIXTIME(dateline - 10800, '%c-%e-%Y') AS period
FROM forum_blog AS blog
WHERE blog.userid IN () AND dateline >= 1311465600 AND dateline < 1315094400
GROUP BY period
);

MySQL Error : 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 ') AND dateline >= 1311465600 AND dateline < 1315094400
GROUP BY period
)' at line 12
Error Number : 1064
Request Date : Tuesday, August 9th 2011 @ 02:39:13 PM
Error Date : Tuesday, August 9th 2011 @ 02:39:13 PM
Script : http://mysite.com/forum/blog.php
Referrer : http://mysite.com/forum/forum.php
IP Address : xx.x.xxx.x
Username : xxxx
Classname : vB_Database
MySQL Version : 5.1.54-0.dotdeb.0-log