Junit: Class not found and junit.framework.AssertionFailedError

(Apple iMac, OSX 10.3.3, IDEA build 1179, JDK_1.4.2_03)

I'm having a few problems with Junit.

If I select the debug option I'm presented with the configuration dialogue. I add a new configuration and call it "TestHelpOnly" and then select the module.

I then select the test class button and open the select class dialouge window. I'm presented with a list of available tests and I select the "TestHelp" class and the fully qualified class path is entered into the form.

I select a temp default working directory and select the display setting and make module check boxes.

I now select the debug button and the Debug window appears and I receive the “Class not found” error message:

If I select the package option and test all classes in the package I get a different result; in that a number of the test run successfully. However, where I try to Mock one of my interfaces I get a “junit.framework.AssertionFailedError: interface is not visible from class loader” message. I have tried deleting the settings and the caches and reinstalling the IDEA and the JDK but without success. Settings: /Users//Library/Preferences/IntelliJ IDEA Caches: /Users/]]>/Library/Caches/IntelliJ IDEA

From other posts it seems that having the junit.jar in the wrong place caused a similar problem however, I have it installed in /library/java/extensions which should not cause a problem.

Anybody ideas?