MustIt must be in the Start Menumenu folders or the Desktop.
As per the Microsoft Support page, http://support.microsoft.com/kb/134552Shortcut key for shortcut does not work:
You are unable to run a shortcut by pressing its shortcut key.
Shortcut keys work only for shortcuts on the desktop or in the Start menu hierarchy.
Make sure that the shortcuts for which you want to use shortcut keys are on the desktop, on the Start menu, or in the Windows\Start Menu\Programs folder.
Shortcut keys work differently depending on the location of the shortcut. If the shortcut is on the desktop or in the Start menu hierarchy, you can use its shortcut key to start the assigned program, or switch to the program if it is already running.
If the shortcut is not on the desktop or in the Start menu hierarchy, you cannot use its shortcut key to start the assigned program, but you can use its shortcut key to switch to the assigned program if it is already running.
NOTE: Shortcut keys may not work for some programs. For example, shortcut keys do not work for items on the Quick Launch bar.