You MUST have the full/recommended load of Quicktime. Just having the player doesn't do it. Go to www.quicktime.com and download QT, when it gets to the loader dialog and asks for Minimum/Recommended/Custom, choose ONLY recommended so that you get the authoring tools for Quicktime. Then you'll be able to read QT files and tif files.
If you do just prefer the player and authoring tools, you can choose the custom option and only select the player and authoring options. Authoring being the must have option. -Shon