the first incoming links admincp

[abbasbsp]

beginning of VB4 Downgrade into vb3, all right
but at the first incoming links admincp, there is always a database error

Database error in vBulletin 4.0.2:

Invalid SQL:

	SELECT COUNT(*) AS count
	FROM attachment AS attachment
	INNER JOIN post AS post USING (postid)
	WHERE attachment.visible = 0;

MySQL Error   : Unknown column 'postid' in 'from clause'
Error Number  : 1054
Request Date  : Sunday, February 28th 2010 @ 07:39:22 AM
Error Date    : Sunday, February 28th 2010 @ 07:39:22 AM
Script        : http://mydomain/admincp/index.php?do=home
Referrer      : http://mydomain/admincp/index.php
IP Address    : 
Username      : bigger
Classname     : vB_Database
MySQL Version : 5.0.89-community

Please help me