NoClassDefFoundError on Java1.5

2011-02-11 12:05:44,676 ERROR [AtlassianEvent::0-BAM::EVENTS:pool-1-thread-5] [NamedThreadFactory] Uncaught exception in thread AtlassianEvent::0-BAM::EVENTS:pool-1-thread-5
java.lang.NoClassDefFoundError: javax/activation/DataSource
at com.atlassian.bamboo.notification.transports.MultipartEmailTransport.sendNotification(MultipartEmailTransport.java:61)
at com.atlassian.bamboo.notification.NotificationDispatcherImpl.dispatchNotifications(NotificationDispatcherImpl.java:59)
at com.atlassian.bamboo.notification.builderror.BuildErrorNotificationListener.handleEvent(BuildErrorNotificationListener.java:72)
at com.atlassian.bamboo.notification.builderror.BuildErrorNotificationListener.handleEvent(BuildErrorNotificationListener.java:19)
at com.atlassian.bamboo.notification.AbstractNotificationEventListener.handleEvent(AbstractNotificationEventListener.java:140)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
at org.springframework.orm.hibernate.HibernateInterceptor.invoke(HibernateInterceptor.java:117)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy225.handleEvent(Unknown Source)
at com.atlassian.event.legacy.LegacyListenerHandler$LegacyListenerInvoker.invoke(LegacyListenerHandler.java:55)
at com.atlassian.event.internal.AsynchronousAbleEventDispatcher$2.run(AsynchronousAbleEventDispatcher.java:60)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:651)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:676)
at com.atlassian.bamboo.build.pipeline.concurrent.NamedThreadFactory$2.run(NamedThreadFactory.java:50)
at java.lang.Thread.run(Thread.java:595)