Hi I have the following problem: I upgraded from 4.0.4 to 4.0.5 used the jems installer files, cause I got some error messages with the ...aop.xml. This error is not coming anymore, but luckily a new one comes, which did not appear on 4.0.4 I use mysql 5.0.27 for persistence and i putted the mysql-ds in the deploy directory and the connector to lib. here is the short version of the error: INFO [WrapperDataSourceService] Bound ConnectionManager 'jboss.jca:service=DataSourceBinding,name=DefaultDS' to JNDI name 'java:DefaultDS' 16:30:19,125 WARN [JBossManagedConnectionPool] Throwable while attempting to get a new connection: null org.jboss.resource.JBossResourceException: Could not create connection; - nested throwable: (com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: ** BEGIN NESTED EXCEPTION ** java.net.UnknownHostException MESSAGE: mysql-hostname: mysql-hostname STACKTRACE: java.net.UnknownHostException: mysql-hostname: mysql-hostname at java.net.InetAddress.getAllByName0(InetAddress.java:1128) at java.net.InetAddress.getAllByName0(InetAddress.java:1098) at java.net.InetAddress.getAllByName(InetAddress.java:1061) at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:137) at com.mysql.jdbc.MysqlIO.(MysqlIO.java:284) at com.mysql.jdbc.Connection.createNewIO(Connection.java:2569) at com.mysql.jdbc.Connection.(Connection.java:1485) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266) ........ and so on over many,many lines Thx Logarith View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3994255#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...