If you have not already done so, you must install Java.
On Windows, CD to the main JRaceman directory and run
java -jar jraceman.jar
or set up a shortcut to jraceman.jar in the main JRaceman directory, with the Start-In directory of the shortcut set to the JRaceman directory.
JRaceman uses a DLL on Windows to access the registry (jRegistryKey.dll). The DLL is in the main JRaceman directory; either this directory must be in your PATH, or your working directory must be the JRaceman directory. Assuming you don't change your PATH to include the JRaceman directory, then if you are running from the command line, you must CD to the JRaceman directory before running jraceman.jar; if you are setting up a shortcut, you must set the Start-In directory (or working directory) of the shortcut to the JRaceman directory.
On Unix, run
java -jar jraceman.jar
If the java binary is not in your PATH, you can explicitly specify the path to it. For example, if you have installed JDK1.3 into /usr/local/jdk1.3, you can run jraceman with the command
/usr/local/jdk1.3/bin/java -jar jraceman.jar
On Solaris 2.6 or later, you can directly run jraceman.jar.