This message after uploading a jar file in Guvnor often means that the classes in the jar depend on some library that is not included. It's hard to say precisely without the jar, but check this possibility (check imports) I'd recommend to upload a jar with just one-two classes with no extra dependences. Hope this helps, Jeff -----Original Message----- From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of rules-users-request(a)lists.jboss.org Sent: Sunday, July 25, 2010 7:43 PM To: rules-users(a)lists.jboss.org Subject: rules-users Digest, Vol 44, Issue 109 Send rules-users mailing list submissions to rules-users(a)lists.jboss.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.jboss.org/mailman/listinfo/rules-users or, via email, send a message with subject or body 'help' to rules-users-request(a)lists.jboss.org You can reach the person managing the list at rules-users-owner(a)lists.jboss.org When replying, please edit your Subject line so it is more specific than "Re: Contents of rules-users digest..." Today's Topics: 1. Re: Uploading models to Guvnor (james corrigan) 2. Re: RuleAgents and containers (Pavel Tavoda) 3. Re: Uploading models to Guvnor (Esteban Aliverti) 4. Re: Uploading models to Guvnor (james corrigan) ---------------------------------------------------------------------- Message: 1 Date: Sun, 25 Jul 2010 20:37:23 +0100 From: james corrigan <jamescorrig(a)gmail.com&gt; Subject: Re: [rules-users] Uploading models to Guvnor To: Rules Users List <rules-users(a)lists.jboss.org&gt; Message-ID: <AANLkTik8gtw+UddxUpyqJvsMpWSks+32bxnAWpC16or1(a)mail.gmail.com&gt; Content-Type: text/plain; charset="iso-8859-1" Hi Mark, Esteban, I recreated the jar and it does contain class files with no manifest file. It has four classes: Temperature, Room, ServerGUI and Fan - i have included it. The four appear in Imported types of the package main menu but i still get the same error when i try to save and validate configuration. Kind regards, James. 2010/7/24 Mark Proctor <mproctor(a)codehaus.org&gt;