The JSFL File API is provided in the form of an extension to the JSAPI. This extension is called a shared library and you can find it in the External Libraries subfolder of your Flash Configuration folder—the filename is FLfile.dll. The location of the Flash Configuration folder differs depending on the operating system installed on your computer. The following list identifies the location of the shared library file:
C:\Documents and Settings\<username>\Local Settings\Application Data\Macromedia\Flash MX 2004\<language>\Configuration\External Libraries\FLfile.dll
C:\Windows\Application Data\Macromedia\Flash MX 2004\<language>\Configuration\ExternalLibraries\FLfile.dll
Hard Drive/Users/<username>/Library/Application Support/Macromedia/Flash MX 2004/<language>/Configuration/ External Libraries\FLfile.dll
For your JSFL scripts to use the File API, Flash MX 2004 7.2 must be installed on the machine that executes the JSFL script.
Note: Don't confuse the shared libraries that contain symbols in your Flash documents with the JSAPI shared libraries. They are two totally different things.