netscape.security.PrivilegeManager is a class that is supplied by netscape. It can be found in java40.jar under your Communicator subdirectory. (usually C:\program files\netscape\communicator\program\java\classes) If you want to use these class files, you'll have to include the jar file in your class path setting. I would suggest determining what you are using the manager for and see if there isn't an equivalent in Sun's JDK for cross browser compatablity. Good Luck