custom component

I tried to modify the pre-built project http://www.cloveretl.com/blog/wp-conten ... mplate.zip, simply changing the message in output but I have the error:

INFO [main] - *** CloverETL framework/transformation graph, (c) 2002-2014 Javlin a.s. ***
INFO [main] - Running with CloverETL library version 3.5.0 build#058 compiled 03/02/2014 14:20:28
INFO [main] - Running on 4 CPU(s), OS Windows 7, architecture amd64, Java version 1.7.0_11, max available memory for JVM 857472 KB
INFO [main] - Loading default properties from: defaultProperties
INFO [main] - Graph definition file: graph/testHelloWorld.grf
ERROR [main] - Error in reading graph from XML !
Unknown component: HELLO_WORLD class: HELLO_WORLD
ERROR [main] - Error details:
org.jetel.exception.XMLConfigurationException
at org.jetel.graph.TransformationGraphXMLReaderWriter.throwXMLConfigurationException(TransformationGraphXMLReaderWriter.java:1117)
at org.jetel.graph.TransformationGraphXMLReaderWriter.instantiatePhases(TransformationGraphXMLReaderWriter.java:533)
at org.jetel.graph.TransformationGraphXMLReaderWriter.read(TransformationGraphXMLReaderWriter.java:417)
at org.jetel.graph.TransformationGraphXMLReaderWriter.read(TransformationGraphXMLReaderWriter.java:317)
at org.jetel.graph.TransformationGraphXMLReaderWriter.loadGraph(TransformationGraphXMLReaderWriter.java:247)
at org.jetel.main.runGraph.main(runGraph.java:402)
Caused by: org.jetel.exception.XMLConfigurationException
at org.jetel.graph.TransformationGraphXMLReaderWriter.throwXMLConfigurationException(TransformationGraphXMLReaderWriter.java:1117)
at org.jetel.graph.TransformationGraphXMLReaderWriter.throwXMLConfigurationException(TransformationGraphXMLReaderWriter.java:1112)
at org.jetel.graph.TransformationGraphXMLReaderWriter.instantiateNodes(TransformationGraphXMLReaderWriter.java:586)
at org.jetel.graph.TransformationGraphXMLReaderWriter.instantiatePhases(TransformationGraphXMLReaderWriter.java:527)
... 4 more
Caused by: java.lang.RuntimeException: Unknown component: HELLO_WORLD class: HELLO_WORLD
at org.jetel.component.ComponentFactory.getComponentClass(ComponentFactory.java:111)
at org.jetel.component.ComponentFactory.createComponent(ComponentFactory.java:128)
at org.jetel.graph.TransformationGraphXMLReaderWriter.instantiateNodes(TransformationGraphXMLReaderWriter.java:571)
... 5 more
Caused by: java.lang.ClassNotFoundException: HELLO_WORLD
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:186)
at org.jetel.component.ComponentFactory.getComponentClass(ComponentFactory.java:101)
... 7 more

ERROR [main] -
--------------------------------- Error details ----------------------------------
Error in reading graph from XML !
Unknown component: HELLO_WORLD class: HELLO_WORLD
----------------------------------------------------------------------------------


Can you help me?
Thanks
Sara