If you reduce the batchsize on your channel there will be more frequent commits of messages by the channels and it will reduce the window of opportunity for a batch to be in-doubt. Also, even if you ...
The Quick Beginnings Guide lists Service Pack 6A as a minimum requirement:
http://www3.ibm.com/software/integration/mqfamily/library/manualsa/amqtac01/
amqtac01tfrm.htm