[rules-users] WorkingMemory deserializing problem.

Hi All, I'm having the following error while deserialing a workingmemory object: java.lang.ClassNotFoundException: com.oss.activation.rules.core.types.StepShadowProxy at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268) at java.lang.ClassLoader.loadClass(ClassLoader.java:251) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:242) at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:584) at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java :1543) at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1465) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java :1698) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1304) com.oss.activation.rules.core.types.Step is one of ower types that are in the WorkingMemory as facts. I don't know about com.oss.activation.rules.core.types.StepShadowProxy, I supose is a DROOLS generated class. Any ideas of what could be wrong here? Thanks! Pedro Costa.