Sorry Alejandro but, after more accurate checks, it looks like it was my mistake. In fact, I forgot to attach the source code in the src folder to the jBPM.jar file during the installation, and now that I've done it, it looks like it works. Thus, the first consequence for this installation error is the impossibility of XML validation, even though the examples begin their tests. Thank you for having replied, Yary View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4219162#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...