Inno: createoleobject on uninstall failed

Question

I'm trying to create an OLE object during uninstall but it keeps failing with the message that MSXML is not installed. However it runs perfectly on install.

begin
  // Create the main MSXML COM Automation object
  try
    XMLHTTP := CreateOleObject('MSXML2.ServerXMLHTTP');
  except
    begin
      Log('Read_Thunderbird_Install_Info() - MSXML was not installed');
      RaiseException('Please install MSXML first.'#13#13
        + '(Error ''' + GetExceptionMessage + ''' occurred)');
    end;
  end;