I have implemented a standard 404.jsp page to display a custom message when a 404 occurs. The application displays the 404 content correctly but I noticed that the error log is being populated with the following message:


Code:
[15/Nov/2011:23:41:26] failure (19868) daily: for host ###.##.##.## trying to GET /ssl/participant/adfaf, service-j2ee reports: org.apache.catalina.core.StandardHostValve@7fa0d111: Exception Processing ErrorPage[errorCode=404, location=/404.jsp]
java.lang.IllegalStateException: PWC3991: getOutputStream() has already been called for this response
	at org.apache.coyote.tomcat5.CoyoteResponse.getWriter(CoyoteResponse.java:684)
	at org.apache.coyote.tomcat5.CoyoteResponseFacade.getWriter(CoyoteResponseFacade.java:210)
	at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:158)
	at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:151)
	at org.apache.jasper.runtime.PageContextImpl.release(PageContextImpl.java:207)
	at org.apache.jasper.runtime.JspFactoryImpl.internalReleasePageContext(JspFactoryImpl.java:143)
	at org.apache.jasper.runtime.JspFactoryImpl.releasePageContext(JspFactoryImpl.java:95)
	at org.apache.jsp.web_005fxml_005f404_jsp._jspService(web_005fxml_005f404_jsp.java:97)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:80)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:915)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:457)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:351)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:915)
	at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:398)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:792)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:474)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:353)
	at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:498)
	at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:387)
	at org.apache.catalina.core.StandardHostValve.postInvoke(StandardHostValve.java:207)
	at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:587)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:556)
	at com.sun.webserver.connector.nsapi.NSAPIProcessor.service(NSAPIProcessor.java:160)
When I run on Tomcat 6.0 I don't see this message in the log. When I run the same code in Oracle's Iplanet WebServer 7.0 then I see the error message above.

Does Anyone know what the deal is here?

Marty