registering the name space was a problem. Thats the reason it was failing.
def groovyUtils = new com.eviware.soapui.support.GroovyUtils( context )
def responseHolder = groovyUtils.getXmlHolder( messageExchange.responseContent )
responseHolder.namespaces['ns2']='
http://www.xyz.com/schemas/xyz/klm';responseHolder.namespaces['ns1']='
http://www.xyz.com/schemas/xyz/def';responseHolder.namespaces['ns4']='
http://www.xyz.com/schemas/xyz/abc';responseHolder.namespaces['ns3']='
http://www.xyz.com/schemas/xyz/pqr';once we have the name spaces we should register them before we get the node value of the response