Nadpisałem pliki 4.1.2, wszedłem w install/upgrade.php, do 37% dochodzi i wyskakuje błąd:

Unexpected Text:

<?xml version="1.0" encoding="windows-1252"?>
<?xml version="1.0" encoding="windows-1252"?>
<errors>
<error><![CDATA[<p>Database Error</p>

Invalid SQL:

(SELECT 'package' AS classtype, package.packageid AS typeid, package.packageid AS packageid,
package.productid AS productid, if(package.productid = 'vbulletin', 1, product.active) AS enabled,
package.class AS class, -1 as isaggregator
FROM package AS package
LEFT JOIN product AS product
ON product.productid = package.productid
WHERE product.active = 1
OR package.productid = 'vbulletin'
)

UNION

(SELECT 'contenttype' AS classtype, contenttypeid AS typeid, contenttype.packageid AS packageid,
1, 1, contenttype.class AS class , contenttype.isaggregator
FROM contenttype AS contenttype
INNER JOIN package AS package ON package.packageid = contenttype.packageid
LEFT JOIN product AS product ON product.productid = package.productid
WHERE product.active = 1
OR package.productid = 'vbulletin' );

Illegal mix of collations (latin2_general_ci,IMPLICIT) and (latin1_swedish_ci,IMPLICIT) for operation '=']]></error>
<error_html><![CDATA[<p>Database error in vBulletin 3.8.7</p>
<p>Invalid SQL:

(SELECT 'package' AS classtype, package.packageid AS typeid, package.packageid AS packageid,
package.productid AS productid, if(package.productid = 'vbulletin', 1, product.active) AS enabled,
package.class AS class, -1 as isaggregator
FROM package AS package
LEFT JOIN product AS product
ON product.productid = package.productid
WHERE product.active = 1
OR package.productid = 'vbulletin'
)

UNION

(SELECT 'contenttype' AS classtype, contenttypeid AS typeid, contenttype.packageid AS packageid,
1, 1, contenttype.class AS class , contenttype.isaggregator
FROM contenttype AS contenttype
INNER JOIN package AS package ON package.packageid = contenttype.packageid
LEFT JOIN product AS product ON product.productid = package.productid
WHERE product.active = 1
OR package.productid = 'vbulletin' );<p>
<p>
<strong>MySQL Error</strong> : Illegal mix of collations (latin2_general_ci,IMPLICIT) and (latin1_swedish_ci,IMPLICIT) for operation '='<br />
<strong>Error Number</strong> : 1267<br />
<strong>Request Date</strong> : Saturday, March 5th 2011 @ 12:00:11 AM<br />
<strong>Error Date</strong> : Saturday, March 5th 2011 @ 12:00:11 AM<br />
<strong>Script</strong> : http://mojastrona/install/upgrade.php<br />
<strong>Referrer</strong> : http://mojastronainstall/upgrade.php<br />
<strong>Classname</strong> : vB_Database<br />
<strong>MySQL Version</strong> : 5.1.54<br />
</p>]]></error_html>
</errors>

Zmień kodowanie na latin2 w nowych tabelach które zostały utworzone.

Pomogło!