Error while generating mail contents

Error while sending mail notification in Apache-continuum-1.2.3

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2009-12-01 13:03:23,798 [pool-1-thread-1] ERROR org.apache.maven.continuum.notification.DefaultContinuumNotificationDispatcher - Error while trying to use the mail notifier.
org.apache.maven.continuum.notification.NotificationException: Error while generating mail contents.
at org.apache.maven.continuum.notification.mail.MailContinuumNotifier.buildComplete(MailContinuumNotifier.java:391)
at org.apache.maven.continuum.notification.mail.MailContinuumNotifier.buildComplete(MailContinuumNotifier.java:288)
at org.apache.maven.continuum.notification.mail.MailContinuumNotifier.sendMessage(MailContinuumNotifier.java:266)
at org.apache.maven.continuum.notification.DefaultContinuumNotificationDispatcher.sendNotification(DefaultContinuumNotificationDispatcher.java:201)
at org.apache.maven.continuum.notification.DefaultContinuumNotificationDispatcher.sendNotification(DefaultContinuumNotificationDispatcher.java:184)
at org.apache.maven.continuum.notification.DefaultContinuumNotificationDispatcher.buildComplete(DefaultContinuumNotificationDispatcher.java:96)
at org.apache.maven.continuum.buildcontroller.DefaultBuildController.endBuild(DefaultBuildController.java:244)
at org.apache.maven.continuum.buildcontroller.DefaultBuildController.build(DefaultBuildController.java:198)
at org.apache.maven.continuum.buildcontroller.BuildProjectTaskExecutor.executeTask(BuildProjectTaskExecutor.java:50)
at org.codehaus.plexus.taskqueue.execution.ThreadedTaskQueueExecutor$ExecutorRunnable$1.run(ThreadedTaskQueueExecutor.java:116)
at edu.emory.mathcs.backport.java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:442)
at edu.emory.mathcs.backport.java.util.concurrent.FutureTask.run(FutureTask.java:178)
at edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1061)
at edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:575)
at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.maven.continuum.installation.InstallationException: cli to get mvn version return code 1
at org.apache.continuum.installation.DefaultInstallationService.getExecutorConfiguratorVersion(DefaultInstallationService.java:436)
at org.apache.maven.continuum.notification.mail.MailContinuumNotifier.getBuilderVersion(MailContinuumNotifier.java:472)
at org.apache.maven.continuum.notification.mail.MailContinuumNotifier.buildComplete(MailContinuumNotifier.java:364)
... 14 more