Files with a .docx extension are files of MS Office 2007. It appears in the form of an archive in most Linux systems today.To view and edit these files in OpenOffice.org,you need to install the OpenXML Translator on your system.You can download the odf converter rpm from http://linux.softpedia.com/progDownload/OpenOffice-org-OpenXML-Translator-Download-30751.html and save it on the disk.Change your directory to the location where you have saved the file. and su to the root account.
# rpm -Uvh odf-converter-versionnumber.rpm
Restart OpenOfiice if its already running and your are done.