Error 0x80070002 applying updates

We are permanently receiving the following error message in System EventLog of a particular server:

Event Type: Error
Event Source: Windows Update Agent
Event Category: Instalación
Event ID: 20
Date:  03/11/2006
Hour:  12:36:11
User:  Not available
Server: HERCULES
Description:
Error de instalación: Windows no puede instalar la siguiente instalación con error 0x80070002: MSXML 6.0 RTM Security Update (925673).

Para obtener más información, vea el Centro de ayuda y soporte técnico en http://go.microsoft.com/fwlink/events.asp.
...

The rest of servers had this update (MSXML 6.0 RTM Security Update 925673)applied without any problem. The problem persists through restarts and the update is permanently shown in system tray bar as pending. We deliver updates using Windows Server Update Services (WSUS) 2.0.

After some research we found KB922582 - Error message when you try to update a Microsoft Windows-based computer: "0x80070002" (last reviewed September 19, 2006).

SYMPTOMS When you try to update a Microsoft Windows-based computer by using any of the following Microsoft tools, you may receive error code 0x80070002:

• The Windows Update Web site
• The Microsoft Update Web site
• The Inventory Tool for Microsoft Updates (ITMU) for Microsoft Systems Management Server (SMS) 2003
• Software Update Services (SUS) 1.0
• Windows Server Update Services (WSUS) 2.0

Nov, 7, 2006 Update: Even though the server experiencing this problem was patched with the former KB922582 and rebooted several times and even re-patched and rebooted once again, the pending MSXML 6.0 RTM Security Update was still there and the error appeared once and again. At the end we decided to manually download the pending update and install it interactively instead of allowing it to be applied through WSUS2.0: Vulnerabilities in Microsoft XML Core Services 6.0 RTM Could Allow Remote Code Execution (925673) The server experiencing this behaviour was a Dell PowerEdge 2950 (Dual Xeon with 4Gb RAM) running Server 2003 R2 x64 Standard and serving SQL Server 2005 Standard as domain controller.

2007-01-12 Update: Too late for me, but if you run into this problem, please see KB910336: You receive a "0x80070002" or "0x80070003" error code after you download an update from Windows Update, from Microsoft Update, or from Windows Server Update Services for more information and resolution about this issue. The article is last reviewed on June 30, 2006 but I couldn't find it when I needed. Maybe you are luckier if you reach this point...