Sorry - in previous email forgot to include the following code, as the NPE occurs when this routine is called at the addPackage call.

private void readDRLintoPackage(String rulesFile) throws DroolsParserException, IOException, Exception {

Reader source = new InputStreamReader(RulesEngine.class.getResourceAsStream("/" + rulesFile));

PackageBuilder builder = new PackageBuilder();

builder.addPackageFromDrl(source);

Package pkg = builder.getPackage();

rules = RuleBaseFactory.newRuleBase();

rules.addPackage(pkg);

}