[rules-users] DSL Troubles

Hi all, I'm using JBoss Rules 4.0.0.12865MR3 and trying to use a DSL expander in my DRL file: package docmap.logic import docmap.facts.* expander test_expander.dsl I didn't forget to also initialize the PackageBuilder: builder.addPackageFromDrl(sourceReader, dslReader) At runtime I always get the following exception, no matter which content the DSL file has: org.drools.rule.InvalidRulePackage: org.drools.lang.ExpanderException@10f3a9corg.drools............ ........................................ <many more ExpanderExceptions> org.drools.lang.ExpanderException@1c9313borg.drools.lang.ExpanderException(a)1bf3519 at org.drools.rule.Package.checkValidity(Package.java:409) Thanks in advance for any hint, Andreas