Stack trace from Jenkins:

Dec 9, 2011 5:03:40 PM hudson.triggers.SCMTrigger$Runner runPolling
SEVERE: Failed to record SCM polling
java.lang.NullPointerException
at hudson.maven.MavenModuleSetBuild.getEnvironment(MavenModuleSetBuild.java:172)
at hudson.scm.SubversionSCM.compareRemoteRevisionWith(SubversionSCM.java:1095)
at hudson.scm.SCM._compareRemoteRevisionWith(SCM.java:355)
at hudson.scm.SCM.poll(SCM.java:372)
at hudson.model.AbstractProject.poll(AbstractProject.java:1324)
at hudson.triggers.SCMTrigger$Runner.runPolling(SCMTrigger.java:420)
at hudson.triggers.SCMTrigger$Runner.run(SCMTrigger.java:449)
at hudson.util.SequentialExecutionQueue$QueueEntry.run(SequentialExecutionQueue.java:118)
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:662)