Log messages containing failed automated backup jobs messages filling up the logs

2016-03-29 02:00:00,166 scheduler_Worker-6 ERROR 
[atlassian.scheduler.core.JobLauncher] Scheduled job with ID 
'AutomatedBackup' failed
java.lang.NullPointerException
         at java.util.Hashtable.put(Hashtable.java:514)
         at java.util.Properties.setProperty(Properties.java:161)
         at 
com.atlassian.crowd.dao.directory.DirectoryPropertiesMapper.exportProperties(DirectoryPropertiesMapper.java:222)
         at 
com.atlassian.crowd.file.FileConfigurationExporter.exportDirectories(FileConfigurationExporter.java:29)
         at 
com.atlassian.crowd.manager.backup.DefaultBackupManager.backup(DefaultBackupManager.java:74)
         at sun.reflect.GeneratedMethodAccessor545.invoke(Unknown Source)
         at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
         at java.lang.reflect.Method.invoke(Method.java:606)
         at 
org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
         at 
org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
         at 
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
         at 
org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
         at 
org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
         at 
org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
         at 
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
         at 
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
         at com.sun.proxy.$Proxy60.backup(Unknown Source)
         at 
com.atlassian.crowd.manager.backup.BackupJobRunner.runJob(BackupJobRunner.java:37)
         at 
com.atlassian.scheduler.core.JobLauncher.runJob(JobLauncher.java:135)
         at 
com.atlassian.scheduler.core.JobLauncher.launchAndBuildResponse(JobLauncher.java:101)
         at 
com.atlassian.scheduler.core.JobLauncher.launch(JobLauncher.java:80)
         at 
com.atlassian.scheduler.quartz1.Quartz1Job.execute(Quartz1Job.java:32)
         at org.quartz.core.JobRunShell.run(JobRunShell.java:223)
         at 
org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:549)