Which version of Quicktime do you have installed?
Also, exactly what is inside 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
Quote from Todd's troubleshooting QuickTime errors blogpost (although it targets AE users, everything is applicable for PrPro), 'QuickTime 7.6.2 or later is required. Don’t be fooled by so-called “QuickTime X”. That doesn’t count'.