Hi kukeltje, first of all thanks for the reply :) 1) I tried a clean jboss 5.1.0 AS and it starts without problems, then I installed jbpm and there are a lot of exception. This is the first one: | 11:40:08,195 WARN [JBossManagedConnectionPool] Throwable while attempting to get a new connection: null | org.jboss.resource.JBossResourceException: Could not create connection; - nested throwable: (org.jboss.resource.JBossResourceException: Class not found for XADataSource com.mysql.jdbc.jdbc2.optional.MysqlXADataSource; - nested throwable: (java.lang.ClassNotFoundException: com.mysql.jdbc.jdbc2.optional.MysqlXADataSource from BaseClassLoader@17704b7{VFSClassLoaderPolicy@d6c6a0{name=vfsfile:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/jbpm/jbpm-service.sar/ domain=ClassLoaderDomain@eb67e8{name=DefaultDomain parentPolicy=BEFORE parent=org.jboss.bootstrap.NoAnnotationURLClassLoader@867e89} roots=[MemoryContextHandler@9068528[path= context=vfsmemory://5c4o03-4x3cun-g2stpfuk-1-g2stpzvd-17 real=vfsmemory://5c4o03-4x3cun-g2stpfuk-1-g2stpzvd-17], FileHandler(a)10536304[path=jbpm/jbpm-service.sar context=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/ real=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/jbpm/jbpm-service.sar/], DelegatingHandler(a)16936351[path=jbpm/jbpm-service.sar/freemarker.jar context=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/ real=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/jbpm/jbpm-service.sar/freemarker.jar], DelegatingHandler(a)7016550[path=jbpm/jbpm-service.sar/jbpm-console-form-plugin.jar context=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/ real=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/jbpm/jbpm-service.sar/jbpm-console-form-plugin.jar], DelegatingHandler(a)16898138[path=jbpm/jbpm-service.sar/jbpm-console-graphView-plugin.jar context=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/ real=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/jbpm/jbpm-service.sar/jbpm-console-graphView-plugin.jar], DelegatingHandler(a)2304605[path=jbpm/jbpm-service.sar/jbpm-console-integration.jar context=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/ real=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/jbpm/jbpm-service.sar/jbpm-console-integration.jar], DelegatingHandler(a)11682775[path=jbpm/jbpm-service.sar/juel-engine.jar context=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/ real=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/jbpm/jbpm-service.sar/juel-engine.jar], DelegatingHandler(a)25425762[path=jbpm/jbpm-service.sar/juel-impl.jar context=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/ real=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/jbpm/jbpm-service.sar/juel-impl.jar], DelegatingHandler(a)15102430[path=jbpm/jbpm-service.sar/juel.jar context=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/ real=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/jbpm/jbpm-service.sar/juel.jar], DelegatingHandler(a)20824308[path=jbpm/jbpm-service.sar/livetribe-jsr223.jar context=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/ real=file:/C:/jbpm-4.2/jboss-5.1.0.GA/server/default/deploy/jbpm/jbpm-service.sar/livetribe-jsr223.jar]] delegates=null exported=[, de.odysseus.el.tree.impl, freemarker, org.jbpm.integration.console.forms, freemarker.ext.dom, de.odysseus.el.tree.impl.ast, org.jbpm.integration.console.graphView, META-INF.maven.org.livetribe.livetribe-jsr223, freemarker.ext.jython, javax.script, freemarker.ext.beans, META-INF.maven.org.jbpm.jbpm4.jbpm-console-integration, META-INF.maven.org.jbpm.jbpm4.jbpm-console-graphView-plugin, de.odysseus.el.tree, freemarker.debug.impl, freemarker.core, META-INF.maven.org.jbpm.jbpm4.jbpm-console-form-plugin, freemarker.ext.servlet, freemarker.ext.util, javax.el, de.odysseus.el.misc, freemarker.debug, freemarker.cache, de.odysseus.el.util, org.jbpm.integration.console, freemarker.ext.xml, META-INF, de.odysseus.el, freemarker.ext.jdom, freemarker.template.utility, freemarker.ext.jsp, freemarker.log, freemarker.ext.rhino, META-INF.services, com.sun.script.juel, freemarker.template, freemarker.ext.ant] <IMPORT-ALL>NON_EMPTY}})) | at org.jboss.resource.adapter.jdbc.xa.XAManagedConnectionFactory.getXAManagedConnection(XAManagedConnectionFactory.java:465) | .... | I think that there's some problem with the mysql connection. Mysql is correctly running on port 3306, what could cause this excepiton? Does JBoss search for connection libraries in a wrong path? Doesn't JBoss have the correct privileges to access the database? Anything else? What could I do to solve? 2) I saw the documentation that you suggested, but I need documentation about the internal pvm's operation. For example, does it work like a state machine or like an Artificial Neural Network? etc. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4268966#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...