Our facility uses Office 2003 with a couple of 07 installations for testing. We occasionally receive Word 07 documents in .docx format which we cannot open using either 03 or 07. Error message is:
"The Office Open XML file *.docx cannot be opened because there are problems with the contents." Pressing the Details button reveals:
"Microsoft Office cannot open this file because the .zip archive file is an unsupported version."
(The documents have not been sent in zipped format as far as I can tell)
Attempting to have Word 07 repair the document fails. Trying web-found suggestions regarding selecting the document and choosing Open and Repair or Recover Text From Any File fail also.