When configuring JNIORs, how you should configure them depends on what Series JNIOR you have. You’ll want to use the JNIOR Web Page for Series 4 JNIORs, and the Java Applet for Series 3 JNIORs.
The Java Applet is a local Java application that can be launched from the Support Tool for each Series 3 JNIOR, while the JNIOR Web Page is a browser accessible configuration for Series 4 JNIORs. Series 3 JNIORs can’t open the JNIOR Web Page because they don’t support the necessary web files required to run the JNIOR Web Page from it. The Java Applet at one point was accessible from a browser, but due to security risks it was changed to be a separate application. Series 4 JNIORs do have the necessary files to open both the Java Applet and the JNIOR Web Page, but you should not use the Java Applet for Series 4 JNIORs. The applets cannot properly configure a Series 4 as the registry settings for many configuration settings are different than what the Series 3 used.