Maven job build that runs on master ends with NPE while sending mails??

[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 262 minutes 52 seconds
[INFO] Finished at: Thu Jan 06 04:47:20 IST 2011
[INFO] Final Memory: 308M/930M
[INFO] ------------------------------------------------------------------------
Waiting for Hudson to finish collecting data
Sending e-mails to: xxx@yyy.com jjj@yyy.com
channel stopped
FATAL: null
java.lang.NullPointerException
at java.lang.String.startsWith(String.java:1421)
at java.lang.String.startsWith(String.java:1450)
at hudson.maven.MavenModuleSetBuild$1.isDescendantOf(MavenModuleSetBuild.java:213)
at hudson.maven.MavenModuleSetBuild$1.<init>(MavenModuleSetBuild.java:182)
at hudson.maven.MavenModuleSetBuild.getChangeSetFor(MavenModuleSetBuild.java:176)
at hudson.maven.FilteredChangeLogSet.<init>(FilteredChangeLogSet.java:51)
at hudson.maven.MavenBuild.getChangeSet(MavenBuild.java:164)
at hudson.model.AbstractBuild.hasParticipant(AbstractBuild.java:316)
at hudson.model.AbstractProject.hasParticipant(AbstractProject.java:1274)
at hudson.model.User.getProjects(User.java:381)
at hudson.scm.MailAddressResolverImpl.findMailAddressFor(MailAddressResolverImpl.java:19)
at hudson.tasks.MailAddressResolver.resolve(MailAddressResolver.java:97)
at hudson.tasks.Mailer$UserProperty.getAddress(Mailer.java:496)
at hudson.tasks.MailSender.buildCulpritList(MailSender.java:383)
at hudson.tasks.MailSender.createEmptyMail(MailSender.java:345)
at hudson.tasks.MailSender.createBackToNormalMail(MailSender.java:169)
at hudson.tasks.MailSender.getMail(MailSender.java:160)
at hudson.tasks.MailSender.execute(MailSender.java:94)
at hudson.maven.MavenModuleSetBuild$RunnerImpl.cleanUp(MavenModuleSetBuild.java:772)
at hudson.model.Run.run(Run.java:1405)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:400)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:145)