Problem:

When attempting to load  and use XA for transaction management (2 phase commit support), console.log has the error message -"Switch Load Module for resource MQXA failed to load RM XA resources, returned pointer was null"

Resolution:

It is necessary to have installed “Client Extended Transaction Support” for WebSphere MQ (or the XA connection will fail in 6.0 SP2 WS1 and above). When installed v7.0.1.9 that has included the Extended Transactional Client and Two phase commit capabilities in MQ clients, MQ doesn't load and you see error in the console log:

130215 22420604       1928 CICTPROD CASXO0019S Switch Load Module for resource "MQSeries support" failed to load RM XA resources, returned pointer was null 22:42:05
130215 22420624       1928 CICTPROD CASXO0023S Severe error detected in "MQSeries support" XA interface, RM interface disabled 22:42:06

Installing MQ 7.5 based client and corresponding configuration changes to ES fixed the MQ error at startup.