Retrieving .docx files from DB (saved as Binary) using ASP.Net

I am Retrieving files that is stored as binary in DB(SQL server 2008) using ASP.Net C#, all files when i Retrieving working perfect except office 2007 files (docx,xlsx, etc). When i retrieve files that are in office 2007, getting message 'The Office Open XML file fn.docx cann't be opened because there are problems with the contents'
and pressing OK and then getting this message
'Word found unreadable content fl.docx. Do you want to record the contents of this document? If you trust the source of this document, Click Yes.'
if my file is in office 2003 or pdf or image or any other format, these are opened absolute fine.
Thanks
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