Hello all, In my program, I receive series of rules as String in XML along with the name of package they should be added to. putRules(String knowledgeSet, List<String> XMLRules) At the moment, I load from the repository the original state of the PackageDescr, get all rule names currently in working memory from the StatefulKnowledgeSession and take out of the PackageDescr what's not in working memory. representation of the PackageDescr and load this one. But... 1) I get the following error when I try to load the latter XML (package node is in the XML, I've checked): Code: XmlPackageReader xmlReader = new XmlPackageReader(null); StringReader sr = new StringReader(documentGlob.asXML()); PackageDescr packageDescr = xmlReader.read(sr); Error: (null: 2, 222): schema_reference.4: Failed to read schema document 'drools.org/drools-5.0.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>. (null: 2, 222): cvc-elt.1: Cannot find the declaration of element 'package'. 2) There is a removeRule function on the KnowledgeBase class, why not addRule, did I miss something? 3) There must be an easier way to do this. Could somebody give me some pointers? All the best, Pierre