Website slows down and hangs completely

Hi All

I am using lenya 2.0.3 with firedocs and tomcat 5.5.28.

My website slows down and hangs out completely after some hits. And I am 
facing this very frequently.

I am getting this error in tomcat logs:

08-Jun-2010 14:44:37 org.apache.jk.common.ChannelSocket processConnection
WARNING: processCallbacks status 2
08-Jun-2010 14:44:37 org.apache.jk.core.MsgContext action
WARNING: Error sending end packet
java.net.SocketException: Broken pipe
     at java.net.SocketOutputStream.socketWrite0(Native Method)
     at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
     at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
     at org.apache.jk.common.ChannelSocket.send(ChannelSocket.java:518)
     at 
org.apache.jk.common.JkInputStream.endMessage(JkInputStream.java:112)
     at org.apache.jk.core.MsgContext.action(MsgContext.java:293)
     at org.apache.coyote.Response.action(Response.java:182)
     at org.apache.coyote.Response.finish(Response.java:304)
     at 
org.apache.catalina.connector.OutputBuffer.close(OutputBuffer.java:281)
     at 
org.apache.catalina.connector.Response.finishResponse(Response.java:476)
     at 
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
     at 
org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:199)
     at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:282)
     at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:754)
     at 
org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:684)
     at 
org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:876)
     at 
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
     at java.lang.Thread.run(Thread.java:595)
08-Jun-2010 14:44:37 org.apache.jk.common.ChannelSocket processConnection
WARNING: processCallbacks status 2

Any suggestions?

TIA

Sachin