I have a simple Grails application that uses MongoDB (without hibernate plugin). On startup I am receiving the following error message. Any help is appreciated.

Code:
Jan 18, 2012 2:28:44 AM org.apache.catalina.core.StandardContext start
SEVERE: Error listenerStart
Jan 18, 2012 2:28:44 AM org.apache.catalina.core.StandardContext start
SEVERE: Context [] startup failed due to previous errors
Jan 18, 2012 2:28:44 AM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [] appears to have started a thread named [MongoCleaner1742391956] but has failed to stop it. This is very likely to create a memory leak.
Jan 18, 2012 2:28:44 AM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SEVERE: The web application [] created a ThreadLocal with key of type [com.mongodb.DBTCPConnector$1] (value [com.mongodb.DBTCPConnector$1@613cc996]) and a value of type [com.mongodb.DBTCPConnector.MyPort] (value [com.mongodb.DBTCPConnector$MyPort@5dd6c8b9]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.