Getting an NPE running maven build.

[workspace] $ /usr/java/default/bin/java -cp /var/lib/hudson/plugins/maven-plugin/WEB-INF/lib/maven-agent-1.352.jar:/apps/apache-maven-2.2.1/boot/classworlds-1.1.jar hudson.maven.agent.Main /apps/apache-maven-2.2.1/ /var/lib/hudson/war/WEB-INF/lib/remoting-1.352.jar /var/lib/hudson/plugins/maven-plugin/WEB-INF/lib/maven-interceptor-1.352.jar 57231 /var/lib/hudson/plugins/maven-plugin/WEB-INF/lib/maven2.1-interceptor-1.2.jar
<===[HUDSON REMOTING CAPACITY]===>���channel started
channel stopped
ERROR: Processing failed due to a bug in the code. Please report this to users@hudson.dev.java.net
java.lang.NullPointerException
at java.util.Hashtable.put(Hashtable.java:394)
at java.util.Hashtable.putAll(Hashtable.java:466)
at hudson.maven.MavenBuilder.call(MavenBuilder.java:156)
at hudson.maven.MavenModuleSetBuild$Builder.call(MavenModuleSetBuild.java:688)
at hudson.maven.MavenModuleSetBuild$Builder.call(MavenModuleSetBuild.java:632)
at hudson.remoting.UserRequest.perform(UserRequest.java:114)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:270)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
project=hudson.maven.MavenModuleSet@1b1dd242[build-clexre-qa1]
project.getModules()=[hudson.maven.MavenModule@61dd9771[build-clexre-qa1/com.picotrading.tech:clexre]]
project.getRootModule()=hudson.maven.MavenModule@61dd9771[build-clexre-qa1/com.picotrading.tech:clexre]
FATAL: null
java.lang.NullPointerException
at java.util.Hashtable.put(Hashtable.java:394)
at java.util.Hashtable.putAll(Hashtable.java:466)
at hudson.maven.MavenBuilder.call(MavenBuilder.java:156)
at hudson.maven.MavenModuleSetBuild$Builder.call(MavenModuleSetBuild.java:688)
at hudson.maven.MavenModuleSetBuild$Builder.call(MavenModuleSetBuild.java:632)
at hudson.remoting.UserRequest.perform(UserRequest.java:114)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:270)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)