BI Server hanging after 100+ hits on reports!

Hi,
Our pentaho BI server hang-on after we hits 100+ reports from web application. And giving massage like"[ContainerBackgroundProcessor[StandardEngine[Catalina]]] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [pentaho] appears to have started a thread named [ObservationManager] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
java.lang.Object.wait(Native Method)
java.lang.Object.wait(Unknown Source)
org.apache.commons.collections.buffer.BlockingBuffer.remove(BlockingBuffer.java:192)
org.apache.jackrabbit.core.observation.ObservationDispatcher.run(ObservationDispatcher.java:153)
java.lang.Thread.run(Unknown Source)

Anybody can suggest for avoid above.

Thanks in Advance!