500 Servlet Exception

[show] java.lang.IllegalStateException: sendError() forbidden after buffer has
been committed.

java.lang.IllegalStateException: sendError() forbidden after buffer has
been committed.
	at com.caucho.server.connection.AbstractHttpResponse.sendError(AbstractHttpResponse.java:496)
	at com.caucho.server.connection.AbstractHttpResponse.sendError(AbstractHttpResponse.java:477)
	at com.caucho.servlets.FileServlet.service(FileServlet.java:246)
	at com.caucho.server.dispatch.ServletFilterChain.doFilter(ServletFilterChain.java:103)
	at com.caucho.server.webapp.DispatchFilterChain.doFilter(DispatchFilterChain.java:97)
	at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:265)
	at com.caucho.server.webapp.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:293)
	at com.caucho.server.webapp.RequestDispatcherImpl.error(RequestDispatcherImpl.java:118)
	at com.caucho.jsp.PageContextImpl.handlePageException(PageContextImpl.java:1163)
	at _jsp._dofus._buy_22ddofus_22dgold__jsp._jspService(_buy_22ddofus_22dgold__jsp.java:121)
	at com.caucho.jsp.JavaPage.service(JavaPage.java:61)
	at com.caucho.jsp.Page.pageservice(Page.java:578)
	at com.caucho.server.dispatch.PageFilterChain.doFilter(PageFilterChain.java:195)
	at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:187)
	at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:265)
	at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:273)
	at com.caucho.server.port.TcpConnection.run(TcpConnection.java:682)
	at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:730)
	at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:649)
	at java.lang.Thread.run(Thread.java:595)