Docx files are actually zipped collections of XML files. XML as a format is unforgiving of data corruption. The main text in docx files is found in document.xml file in the collection. Damaged docx2txt uses CakeCMD , an unzipper that will unzip partially corrupt document.xml files. Also the Perl routine used to extract the text from the document.xml file doesn't care about well-formedness of the XML, a stumbling block of Word 2007 and 2010.
Microsoft .NET Framework 2.0