When I leave a SFSB for long without invoking a @Remove annotated method the server (AS6.1.0.Final) complains it can't find the class org.jboss.cache.Fqn, which I understand is part of the caching implementation.

Caused by: java.lang.ClassNotFoundException: org.jboss.cache.Fqn from BaseClassLoader@752b5a{vfs:///usr/local/java/jbossas/jboss-6.1.0.Final/server...

At first I tought it happened when trying to passivate, but after redeploying with a log in a @PrePassivate method it was never called

@PrePassivate
public void pasivando() {
    logger.info("Entering passivation...");
}

org.jboss.cache.Fqn is found in two libraries, but none of them are to be found in the server. Should I just copy any of them somewhere in the server?

I've attached the full log in case it might be of any help, which it doesn't say much than

16:42:00,433 FATAL [org.jboss.serial.persister.RegularObjectPersister] error: java.lang.reflect.InvocationTargetException
    at sun.reflect.GeneratedMethodAccessor903.invoke(Unknown Source) [:1.6.0_26]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_26]
    at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_26]
    at org.jboss.serial.persister.RegularObjectPersister.writeSlotWithMethod(RegularObjectPersister.java:120) [:6.1.0.Final]
    at org.jboss.serial.persister.RegularObjectPersister.defaultWrite(RegularObjectPersister.java:86) [:6.1.0.Final]
    at org.jboss.serial.persister.RegularObjectPersister.writeData(RegularObjectPersister.java:62) [:6.1.0.Final]
    at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.describeObject(ObjectDescriptorFactory.java:276) [:6.1.0.Final]
...
Caused by: java.lang.NoClassDefFoundError: org/jboss/cache/Fqn
    at java.lang.Class.getDeclaredMethods0(Native Method) [:1.6.0_26]
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2427) [:1.6.0_26]
    at java.lang.Class.getDeclaredMethod(Class.java:1935) [:1.6.0_26]
    at org.jboss.serial.classmetamodel.ClassMetaData.lookupMethodOnHierarchy(ClassMetaData.java:102) [:6.1.0.Final]
    at org.jboss.serial.classmetamodel.ClassMetaData.lookupInternalMethods(ClassMetaData.java:432) [:6.1.0.Final]
    at org.jboss.serial.classmetamodel.ClassMetaData.<init>(ClassMetaData.java:122) [:6.1.0.Final]
    at org.jboss.serial.classmetamodel.ClassMetamodelFactory.getClassMetaData(ClassMetamodelFactory.java:350) [:6.1.0.Final]
    at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.describeObject(ObjectDescriptorFactory.java:168) [:6.1.0.Final]
    at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectOutput.writeObject(DataContainer.java:206) [:6.1.0.Final]
    at org.jboss.serial.persister.ArrayPersister.saveObjectArray(ArrayPersister.java:110) [:6.1.0.Final]
    at org.jboss.serial.persister.ArrayPersister.writeData(ArrayPersister.java:101) [:6.1.0.Final]
    at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.describeObject(ObjectDescriptorFactory.java:276) [:6.1.0.Final]
    at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectOutput.writeObject(DataContainer.java:206) [:6.1.0.Final]
    at org.jboss.serial.persister.RegularObjectPersister.writeSlotWithFields(RegularObjectPersister.java:182) [:6.1.0.Final]
    at org.jboss.serial.persister.ObjectOutputStreamProxy.writeFields(ObjectOutputStreamProxy.java:79) [:6.1.0.Final]
    at org.jboss.serial.persister.ObjectOutputStreamProxy.defaultWriteObject(ObjectOutputStreamProxy.java:68) [:6.1.0.Final]
    at java.util.Vector.writeObject(Vector.java:1012) [:1.6.0_26]
    ... 206 more
Caused by: java.lang.ClassNotFoundException: org.jboss.cache.Fqn from BaseClassLoader@752b5a{vfs:///usr/local/java/jbossas/jboss-6.1.0.Final/server/default/deploy/application-1.1.0.Alfa2-SNAPSHOT.ear/application-war-1.1.0.Alfa2-SNAPSHOT.war/}
    at org.jboss.classloader.spi.base.BaseClassLoader.loadClass(BaseClassLoader.java:480) [jboss-classloader.jar:2.2.1.GA]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247) [:1.6.0_26]
    ... 223 more

Thanks in advance.