This has to do with QuickTime not being installed on your computer. From Windows Vista and up, Windows added an administration option by default. This is like an extra safeguard so files will not be moved or altered by, let's say viruses. All you have to do is right click on the program icon and select "run as administrator" and the program will open.
A few other things to check for:
1) Install QuickTime and make sure to associate your filetypes to QuickTime as a default.
2) Go to any folder, select Tools>Folder options>View> and make sure "hide extensions for known filetypes" is UN-checked.