It would appear that whoever gave you the QuickTime files has altered the properties, to allow it to display properly in the player. Load in your footage again go to properties and select the video track. Uncheck the aspect ratio box and change the 1024 to 720, hit return then recheck the aspect box.
You will now have a proper anamorphic file whic will work properly in FCP.
Hope this helps
Roddy Jamieson