I am trying to build and deploy a sample jBPM process download from jBPM6 - Custom Work Item: Hello Process Example, but am getting error as below. It seems like the work item handler class appear in the wrong package but i am just using the source downloaded from jboss community directly, please help

15:55:42,078 ERROR [stderr] (pool-36-thread-7) Exception in thread "pool-36-thread-7" java.lang.NoClassDefFoundError: target/classes/com/sample/HelloProcessExtension (wrong name: com/sample/HelloProcessExtension)

15:55:42,078 ERROR [stderr] (pool-36-thread-7) at java.lang.ClassLoader.defineClass1(Native Method)

15:55:42,078 ERROR [stderr] (pool-36-thread-7) at java.lang.ClassLoader.defineClass(ClassLoader.java:616)

15:55:42,078 ERROR [stderr] (pool-36-thread-7) at java.lang.ClassLoader.defineClass(ClassLoader.java:462)