Is that the only information in the error? Is there any stack trace available?
Yes, this was the only information in the error.
Eventually got around the problem though. I used the jboss-client.jar from the older version which was using the Jboss remoting version 4.0.18, instead of 5.0.5.
I believe this was a problem in the collectd side, as I was able to connect using visualvm using the updated jar.