(1) Your Browser is blocking the content from being downloaded. If you are using IE check that there isn't a status bar at the top of the window indicating that it is blocking "active content"

(2) Java runtime is not installed or set up correctly on your computer
You can download the latest JRE (java runtime environment) from:
http://java.sun.com/j2se/1.4.2/download.html

(3) Your firewall is blocking the tuner from downloading

If you are still having problems, try downloading and installing the applet directly on your computer. You can download the zip file here

You will need a decompression utility on your computer to unzip the downloaded file. If you do not have such a utility an excellent one, "WinRar", is available for download at:
http://www.rarlab.com

Extract the zip file to a temporary directory, then double click the "HarpTuner.exe" file. You can accept the default directory or specify an alternative one on your hard drive and unzip the applet into it. To start the applet, move to the installation directory and double click on the "HarpTuner.html" page.