NoClassDefFoundError

I created a jar w/ the following code in cmd

jar cvmf test.jar manifest.txt *.class

and the manifest file reading:

Main-Class: JarTest

In the manifest file I do have an extra line. This is a swing application so when I double click it in Windows it should start. However, nothing happened so I decided to run it from the CMD and I got

Exception in thread "main" java.lang.NoClassDefFoundError: JarTest$1

at JarTest.main(JarTest.java:660)

Note: When the jar was created no error's were given.

[543 byte] By [P.F.a] at [2007-11-26 19:53:53]