Mail error

I was trying to answer some reader email and got an error message I've never seen before. Has something changed? Here's the message: HTTP Status 500 - type Exception report message description The server encountered an internal error () that prevented it from fulfilling this request. exception java.lang.IllegalStateException org.apache.catalina.connector.ResponseFacade.sendRedirect(ResponseFacade.java:432) org.apache.taglibs.standard.tag.common.core.RedirectSupport.doEndTag(Unknown Source) org.apache.jsp.tag.web.infra.handleError_tag._jspx_meth_c_redirect_1(org.apache.jsp.tag.web.infra.handleError_tag:273) org.apache.jsp.tag.web.infra.handleError_tag._jspx_meth_c_when_1(org.apache.jsp.tag.web.infra.handleError_tag:249) org.apache.jsp.tag.web.infra.handleError_tag._jspx_meth_c_choose_0(org.apache.jsp.tag.web.infra.handleError_tag:178) org.apache.jsp.tag.web.infra.handleError_tag.doTag(org.apache.jsp.tag.web.infra.handleError_tag:102) org.apache.jsp.h.search._jspService(org.apache.jsp.h.search:133) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97) javax.servlet.http.HttpServlet.service(HttpServlet.java:802) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264) javax.servlet.http.HttpServlet.service(HttpServlet.java:802) com.zimbra.webClient.filters.CharEncodingFilter.doFilter(CharEncodingFilter.java:45) com.zimbra.webClient.filters.SetHeaderFilter.doFilter(SetHeaderFilter.java:322) note The full stack trace of the root cause is available in the Apache Tomcat/5.5.15 logs.