Be sure that derby.jar is either:
- in the groovy lib folder
- explicitly set in the classpath (ie. set CLASSPATH=%CLASSPATH%;/path/to/derby.jar)
- loaded at runtime (ie. this.class.classLoader.rootLoader.addURL(new URL("file:derby.jar")) )
If you are using JDK 1.5 or greater, a LinkageError will occur. Removing the mx4j-3.0.2.jar library from %GROOVY_HOME%\lib will make it work again, but a better solution would be preferable.
Look at http://jira.codehaus.org/browse/GROOVY-2303 for further information, or ask on the email@example.com.