According to Microsoft Knowledge Base Article - 238413

http://support.microsoft.com/default.aspx
scid=http://support.microsoft.com:80/support/kb/articles/Q2
38/4/13.ASP&NoWebContent=1

"Important The Msicu.exe and Msicuu.exe utilities are not
supported on systems where Microsoft Windows Installer 2.0
or later is installed, including Microsoft Windows XP.
Follow these steps to verify your version of the Windows
Installer:"

Microsoft Windows Installer 2.0 or later is installed in
my system. How do I cleanup Microsoft Windows Installer
2.0 or later settings other than downgrading to an earlier
version such as 1.1?

If you have Windows Installer (MSI) version 2.0, then use msizap.exe version
2.0.2600 or greater as the cleanup. The cleanup utility (msicu.exe or
msicuu.exe) does not support Windows Installer version 2.0. The only major
difference between the two is that msicuu.exe provides a graphical interface.
Underneath it uses msizap.exe.

All you need to do is obtain the latest version of MSIZAP.EXE (minimum version
of 2.0.2600.0). This tool is found in the Windows Installer SDK at <
http://www.microsoft.com/msdownload/...sdk/sdkupdate/ >. Instructions on
how to use the tool can be found in the Windows Installer MSDN documentation at
<
http://msdn.microsoft.com/library/de...msizap_exe.asp
>.

Additionally, if you have Windows XP, MSIZAP.EXE is included as a utility in the
support tools installation package with some additional documentation included
in suptools.chm (will be found in the %windir%\help folder after installing the
package).

Note that MSIZAP.EXE is a last-resort utility and if used incorrectly can affect
other applications on the machine.

Hope this helps,
- Carolyn Napier
Microsoft Windows Installer Team

--
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MSI FAQ:
<http://www.microsoft.com/windows2000/community/centers/management/msi_faq.mspx>

"M.Chiessi" <(E-Mail Removed)> wrote in message
news:6b4401c3e683$9f6ed150$(E-Mail Removed)...
> According to Microsoft Knowledge Base Article - 238413
>
> http://support.microsoft.com/default.aspx?
> scid=http://support.microsoft.com:80/support/kb/articles/Q2
> 38/4/13.ASP&NoWebContent=1
>
> "Important The Msicu.exe and Msicuu.exe utilities are not
> supported on systems where Microsoft Windows Installer 2.0
> or later is installed, including Microsoft Windows XP.
> Follow these steps to verify your version of the Windows
> Installer:"
>
> Microsoft Windows Installer 2.0 or later is installed in
> my system. How do I cleanup Microsoft Windows Installer
> 2.0 or later settings other than downgrading to an earlier
> version such as 1.1?