If you think you changed a file's icon with the Binder, but you do not see the change in the File Manager, make sure that you restarted the File Manager after you saved the Binder changes. If you have already restarted the File Manager, recheck your changes with the Binder. Make sure the entry you changed was saved to your user database with the Binder Save button. Also, make sure the file displayed really falls into the class of files changed with the Binder.
If your File Manager displays only the three generic types of icons (folders, applications, and documents), the File Manager was unable to connect with the Binder database. Check your Console window for error messages indicating where the problem occurred.