First of all, i'm sorry if i'm not posting in the correct forum. I do not know where JBOss Rules user exchange infos here. Anyway, i'm facing a problem when i'm following the trailblazer demos "Extending the simple credit system example with its own Domain Specific Language". I managed to get the first demo running smoothly. I followed the demo (the one using a Domain Specific Language) step by step but i couldn't get mine to run without exception (i paste it below for your reference). java.lang.IllegalArgumentException: Unable to use expander. Make sure a expander or dsl config is being passed to the parser. [ExpanderResolver was not set]. at org.drools.lang.RuleParser.expander(Unknown Source) at org.drools.lang.RuleParser.prolog(Unknown Source) at org.drools.lang.RuleParser.compilation_unit(Unknown Source) at org.drools.compiler.DrlParser.compile(Unknown Source) at org.drools.compiler.DrlParser.parse(Unknown Source) at org.drools.compiler.DrlParser.parse(Unknown Source) at org.drools.compiler.PackageBuilder.addPackageFromDrl(Unknown Source) at com.livetrail.CreditExample.main(CreditExample.java:21) Is this a known issue? or am i doing it wrong? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3982260#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...