Office Open XML was created on 2006-12-07.

Office Open XML Converter was created on 2008-07-03.

In computer lingo XML stands for Extensible Markup Language. It is a textual data format and is used in interchanging data over the Internet. XML-based formats have become the default for most office-productivity tools, including Microsoft Office (Office Open XML), OpenOffice.org (OpenDocument), and Apple's iWork.

Open XML Paper Specification was created in 2006-10.

If you open the xml in most web browser it will state an error code denoting the type of malformation of the xml.

you can use an xml tool like an xml editor to validate and correct your xml.