> UPDATE ((AttrValue LEFT JOIN Node ON AttrValue.Node = Node.id)
> LEFT JOIN Attribute ON AttrValue.Attribute = A2Attribute.id)
> LEFT JOIN NodeType ON Node.NodeType = NodeType.id
> SET AttrValue.attrValue = 'C:\Program Files\DIR\Application\Archi'
> WHERE (((NodeType.description)='SystemSettings')
> AND ((Node.description)='GlobalPath')
> AND ((Attribute.description)='SettingValue'));

UPDATE
AttrValue
SET
attrValue = 'C:\Program Files\DIR\Application\Archi'
WHERE
EXISTS(SELECT 1 FROM Node
JOIN Attribute ON (AttrValue.Attribute = A2Attribute.id)
JOIN NodeType ON (Node.NodeType = NodeType.id)
WHERE
AttrValue.Node = Node.id and
NodeType.description = 'SystemSettings' and
Node.description = 'GlobalPath' and
Attribute.description = 'SettingValue');

Regards,
Arno