Hi, I have this *weird* error that I get when trying to compile my app: Mar 12, 2013 3:55:17 AM org.jboss.errai.marshalling.rebind.MarshallerGeneratorFactory generate INFO: generating marshalling class... java.lang.RuntimeException: error loading marshalling extension: org.jboss.errai.enterprise.rebind.ObserversMarshallingExtension at org.jboss.errai.marshalling.rebind.MarshallerGeneratorFactory._generate(MarshallerGeneratorFactory.java:213) at org.jboss.errai.marshalling.rebind.MarshallerGeneratorFactory.generate(MarshallerGeneratorFactory.java:142) at org.jboss.errai.marshalling.rebind.MarshallersGenerator._generate(MarshallersGenerator.java:272) at org.jboss.errai.marshalling.rebind.MarshallersGenerator.generateMarshallerBootstrapper(MarshallersGenerator.java:250) at org.jboss.errai.marshalling.rebind.MarshallersGenerator.generate(MarshallersGenerator.java:235) at com.google.gwt.core.ext.GeneratorExtWrapper.generate(GeneratorExtWrapper.java:48) However my app works fine when I run it with DevMode. What could be the solution for this? Cheers.