[rules-users] Rule exception

Hi all, I've got problem with the following rule rule 'Satellite mediation' when PricingField(name=="srv", eval(strValue.contains("VOIX"))) $field : PricingField( name == "duree") then mediationManager.addLine(11,$field.getIntValue()); end I've got this exception when this rule is use java.lang.AbstractMethodError: Mediation.Rule_Satellite_mediation_0ReturnValue0Invoker.evaluate(Ljava/lang/Object;Lorg/drools/spi/Tuple;[Lorg/drools/rule/Declaration;[Lorg/drools/rule/Declaration;Lorg/drools/WorkingMemory;)Z at org.drools.rule.PredicateConstraint.isAllowed(PredicateConstraint.java:210) at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:132) at org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:317) at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:140) at org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:298) at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:153) at org.drools.reteoo.Rete.assertObject(Rete.java:177) at org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:192) at org.drools.reteoo.ReteooWorkingMemory.doInsert(ReteooWorkingMemory.java:71) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:886) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:858) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:659) What's wrong?