I receive the same error on both my Windows and Linux boxes when I try to run the java client by itself. However, through a browser it works fine. C:\>java vncviewer HOST 172.16.0.13 PORT 5903 Exception in thread "main" java.lang.NoClassDefFoundError: vncviewer [root@apache1 root]$ java vncviewer Exception in thread "main" java.lang.NoClassDefFoundError: vncviewer What am I missing here? Mark