New to Java

I'm looking to convert a file with .rrd extension to .jrb extension. The process is mentioned in this page

[http://oldwww.jrobin.org/utilities/convertor.html|http://oldwww.jrobin.org/utilities/convertor.html]

and I guess its for linux.

I did the following,

C:\rrdtool>java -jar convertor-1.5.9.1.jar
Exception in thread "main" java.lang.NoClassDefFoundError: org/jrobin/core/RrdEx
ception
Caused by: java.lang.ClassNotFoundException: org.jrobin.core.RrdException
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: org.jrobin.convertor.Convertor. Program will exit
.

C:\rrdtool>path.bat

C:\rrdtool>set path=C:\Program Files\Java\jdk1.6.0\bin;

C:\rrdtool>set classpath=C:\Program Files\Java\jdk1.6.0\lib;

C:\rrdtool>java -jar convertor-1.5.9.1.jar
Exception in thread "main" java.lang.NoClassDefFoundError: org/jrobin/core/RrdException

Now what does this mean? What do I do to make this work.