Release project fails in run-release-prepare-goals

Releasing a "Web application " project (1 pom.xml) fails always during run-release-prepare-goals
with exception :
[INFO] Transforming 'xxxxx xxxxx xxxx Applications'...
[INFO] Not generating release POMs
[ERROR] org.apache.maven.shared.release.ReleaseExecutionException: Maven execution failed, exit code: '1'
at org.apache.continuum.release.phase.AbstractContinuumRunGoalsPhase.execute(AbstractContinuumRunGoalsPhase.java:70)
at org.apache.continuum.release.phase.RunPrepareGoalsPhase.execute(RunPrepareGoalsPhase.java:47)
at org.apache.maven.shared.release.DefaultReleaseManager.prepare(DefaultReleaseManager.java:194)
at org.apache.maven.shared.release.DefaultReleaseManager.prepareWithResult(DefaultReleaseManager.java:107)
at org.apache.maven.continuum.release.executors.PrepareReleaseTaskExecutor.execute(PrepareReleaseTaskExecutor.java:43)
at org.apache.maven.continuum.release.executors.AbstractReleaseTaskExecutor.executeTask(AbstractReleaseTaskExecutor.java:67)
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(Thread.java:595)
Caused by: org.apache.maven.shared.release.exec.MavenExecutorException: Maven execution failed, exit code: '1'
at org.apache.continuum.utils.shell.DefaultShellCommandHelper.executeGoals(DefaultShellCommandHelper.java:212)
at org.apache.continuum.utils.shell.DefaultShellCommandHelper.executeGoals(DefaultShellCommandHelper.java:172)
at org.apache.continuum.release.phase.AbstractContinuumRunGoalsPhase.execute(AbstractContinuumRunGoalsPhase.java:62)
... 11 more

in continuum log file i find :
2009-04-15 13:13:47,880 [pool-3-thread-1] INFO shellCommandHelper - Executing: /bin/sh -c cd /data/continuum/working/336 && mvn -Dmaven.repo.local=/data/continuum/user/purl clean integration-test --no-plugin-updates --batch-mode

if i run this manually (as same user as tomcat is running in) , no problem.