NullPointerException thrown from CXF DocLiteralInInterceptor

Issue

When I invoke the endpoint using a JAX-WS client, I get the following error:

2013-11-26 10:03:39,462 243006 WARNING [org.apache.cxf.phase.PhaseInterceptorChain] (pool-38-thread-1:) Interceptor for {http://REDACTED has thrown exception, unwinding now
java.lang.NullPointerException
        at org.apache.cxf.staxutils.StaxUtils.toNextElement(StaxUtils.java:333)
        at org.apache.cxf.interceptor.DocLiteralInInterceptor.handleMessage(DocLiteralInInterceptor.java:80)
        at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:243)
        at org.apache.cxf.endpoint.ClientImpl.onMessage(ClientImpl.java:755)
        at org.apache.cxf.transport.http.HTTPConduit$WrappedOutputStream.handleResponseInternal(HTTPConduit.java:2408)
        at org.apache.cxf.transport.http.HTTPConduit$WrappedOutputStream.handleResponse(HTTPConduit.java:2278)
        at org.apache.cxf.transport.http.HTTPConduit$WrappedOutputStream.close(HTTPConduit.java:2121)
        at org.apache.cxf.transport.AbstractConduit.close(AbstractConduit.java:66)
        at org.apache.cxf.transport.http.HTTPConduit.close(HTTPConduit.java:695)
        at org.apache.cxf.interceptor.MessageSenderInterceptor$MessageSenderEndingInterceptor.handleMessage(MessageSenderInterceptor.java:62)
        at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:243)
        at org.apache.cxf.endpoint.ClientImpl.invoke(ClientImpl.java:516)
        at org.apache.cxf.endpoint.ClientImpl.invoke(ClientImpl.java:313)
        at org.apache.cxf.endpoint.ClientImpl.invoke(ClientImpl.java:265)
        at org.apache.cxf.frontend.ClientProxy.invokeSync(ClientProxy.java:73)
        at org.apache.cxf.jaxws.JaxWsClientProxy.invoke(JaxWsClientProxy.java:124)
        at $Proxy1346.tenprintSearchResponse(Unknown Source)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at my.app.ClientThing.run(MessageRouterTask.java:44)
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
        at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
        at java.util.concurrent.FutureTask.run(Unknown Source)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(Unknown Source)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)