I'm currently installing a WAS 5.1 environement and testing MQ communications.
WAS 5.1 was installed with internal Websphere MQ
When I create a new server in WAS a new QueueManager is created as WAS_node_application_name and this Queue manager works fine.
(I've tested it with postCard test application)
But when I try to send a message it fail with following error :
javax.jms.JMSException: MQJMS2005: Impossible de créer MQQueueManager pour 't22.TMHE.COM:WAS_t22_TMHE_Parts_Portal'
com.ibm.mq.MQException: MQJE001 : MQException : Code achèvement 2, raison 2059 MQJE011 : Tentative de connexion au socket refusée
"Connection refused"... that means the code was trying to connect to server X at port Y, but there was no answer. Either server X is not running, or it's not listening at port Y, or there is a firewall preventing the connection.
So you'll have to check out the configuration which specifies X and Y for your environment. See if the server is really listening there. Check out your network if necessary.