Where exactly did you get the file?
Read Bill Hunt on a file type as WRAPPER http://forums.adobe.com/thread/440037
What is a CODEC... a Primer http://forums.adobe.com/thread/546811
What CODEC is INSIDE that file? http://forums.adobe.com/thread/440037
Report back with the codec details of your file, use the programs below... a screen
shot works well to SHOW people what you are doing
For PC http://mediainfo.sourceforge.net/en or http://www.headbands.com/gspot/
For Mac http://mediainspector.massanti.com/