Product Installer Issues

The source installation package for the product [product name] is out of sync with the client package. Try the installation again using a valid copy of the installation package '[package name]'.

Unable to uninstall old version of [product name]. Please uninstall it yourself using Control Panel Add-Remove Programs before attempting to install this product.

If you receive these message when installing or uninstalling it implies the product install has been corrupt on your system. Microsoft provides a utility to help uninstall corrupt product installs:
http://support.microsoft.com/mats/Program_Install_and_Uninstall

Note: The tool only removes the corrupt installer information, so you may also have to manually delete the Liquid Xml folder from the install folder (typically \Program Files\Liquid Xml...).