Hi Guys, Iam using Eclipse tool for writing drl , i have written drl . Then i have written an ant script to convert this drl to PKG . i have used drools5.1.1.jars. i was sucessfully convert drl to pkg. knowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); kbuilder.add( ResourceFactory.newFileResource( "c:/Sample.pkg" ), ResourceType.PKG ); iam getting below error: java.lang.ClassCastException: org.drools.reteoo.ReteooRuleBase cannot be cast to org.drools.rule.Package at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:487) at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28) at com.test.rules.MyRulesEngine.<init>(MyRulesEngine.java:51) at com.test.rules.MyRulesEngine.getInstance(MyRulesEngine.java:39) at com.test.rules.MyRulesExecuter.main(MyRulesExecuter.java:38) Can anybody help resolving my problem.. Thanks prasad