[rules-users] Problem drools-ant 4.0.2

I try to generate a pkg file from a drl file so , i'm using drools-ant task (version 4.0.2) when i load my pkg file, there's a classcast exception: java.lang.ClassCastException: org.drools.reteoo.ReteooRuleBase cannot be cast to org.drools.rule.Package at org.drools.agent.FileScanner.readPackage(FileScanner.java:109) at org.drools.agent.FileScanner.getChangeSet(FileScanner.java:79) at org.drools.agent.FileScanner.loadPackageChanges(FileScanner.java:57) at org.drools.agent.RuleAgent.checkForChanges(RuleAgent.java:330) at org.drools.agent.RuleAgent.refreshRuleBase(RuleAgent.java:298) at org.drools.agent.RuleAgent.configure(RuleAgent.java:284) at org.drools.agent.RuleAgent.init(RuleAgent.java:208) at org.drools.agent.RuleAgent.newRuleAgent(RuleAgent.java:176) at org.drools.agent.RuleAgent.newRuleAgent(RuleAgent.java:148) at fr.biomerieux.qi.algo.common.inferenceengine.InferenceEngineControllerImpl.initializeRuleBaseFromPKG (InferenceEngineControllerImpl.java:128) at fr.biomerieux.qi.algorithms.testcase.inferenceengine.InferenceEngineTestCase.testInferenceEngineCase (InferenceEngineTestCase.java:52) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at junit.framework.TestCase.runTest(TestCase.java:154) at junit.framework.TestCase.runBare(TestCase.java:127) at junit.framework.TestResult$1.protect(TestResult.java:106) at junit.framework.TestResult.runProtected(TestResult.java:124) at junit.framework.TestResult.run(TestResult.java:109) at junit.framework.TestCase.run(TestCase.java:118) at fr.biomerieux.junit.BmxTestCase.run(BmxTestCase.java:64) at junit.framework.TestSuite.runTest(TestSuite.java:208) at junit.framework.TestSuite.run(TestSuite.java:203) at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run( JUnit3TestReference.java:130) at org.eclipse.jdt.internal.junit.runner.TestExecution.run( TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests( RemoteTestRunner.java:460) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests( RemoteTestRunner.java:673) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run( RemoteTestRunner.java:386) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main( RemoteTestRunner.java:196)