From http://www.jboss.org/j2ee/schema/jboss_5_1.xsd :

-----8<-----------------------------------------------------------------
<jboss xmlns="http://www.jboss.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.jboss.org/j2ee/schema
http://www.jboss.org/j2ee/schema/jboss_5_0.xsd"
version="5.0">
...
</jboss>

The instance documents may indicate the published version of
the schema using the xsi:schemaLocation attribute for the
Java EE namespace with the following location:

http://www.jboss.org/j2ee/schema/jboss_5_0.xsd
-----8<-----------------------------------------------------------------

Both should be jboss_5_1.xsd, and version="3.0", right?