Communications link failure error

Hello ,

I am using version 6.4 tomcat bundle with mysql database .When I start my process after two or three tasks bpm started giving me following exceptions.

Can anybody help me where I am lacking in configurations .

1. org.quartz.JobPersistenceException: Failed to obtain DB connection from data source 'notManagedDS': java.sql.SQLException: Could not retrieve datasource via JNDI url 'java:comp/env/bonitaSequenceManagerDS' com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

2. java.net.SocketException: No buffer space available (maximum connections reached?): connect
   at java.net.DualStackPlainSocketImpl.connect0(Native Method)
   at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
   at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
   at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
   at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
   at java.net.PlainSocketImpl.connect(Unknown Source)
   at java.net.SocksSocketImpl.connect(Unknown Source)
   at java.net.Socket.connect(Unknown Source)
   at java.net.Socket.connect(Unknown Source)
   at java.net.Socket.(Unknown Source)
   at java.net.Socket.(Unknown Source)
   at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)

3. Last packet sent to the server was 0 ms ago.]
   at org.quartz.impl.jdbcjobstore.JobStoreCMT.getNonManagedTXConnection(JobStoreCMT.java:168)
   at org.quartz.impl.jdbcjobstore.JobStoreSupport.doRecoverMisfires(JobStoreSupport.java:3169)
   at org.quartz.impl.jdbcjobstore.JobStoreSupport$MisfireHandler.manage(JobStoreSupport.java:3935)
   at org.quartz.impl.jdbcjobstore.JobStoreSupport$MisfireHandler.run(JobStoreSupport.java:3956)
   Caused by: java.sql.SQLException: Could not retrieve datasource via JNDI url 'java:comp/env/bonitaSequenceManagerDS' com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION **