请帮忙看看这段日志说明什么问题？
2007-4-1 20:06:17 org.apache.jk.core.MsgContext action
警告: Error sending end packet
java.net.SocketException: Software caused connection abort: socket write error
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:531)
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.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:204)
at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:282)
at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:767)
at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:697)
at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:889)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)
2007-4-1 20:06:17 org.apache.jk.common.ChannelSocket processConnection
警告: processCallbacks status 2
2007-4-1 20:06:24 org.apache.jk.core.MsgContext action
警告: Error sending end packet
java.net.SocketException: Software caused connection abort: socket write error
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:531)
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.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:204)
at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:282)
at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:767)
at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:697)
at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:889)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)
2007-4-1 20:06:24 org.apache.jk.common.ChannelSocket processConnection
警告: processCallbacks status 2
2007-4-1 22:03:25 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at org.apache.jsp.UserAdmin.adddata.save_jsp._jspService(save_jsp.java:113)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:334)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)