Getting a server error when trying to setup email alert

When logged on to the website to configure email alerts keep getting the error message below. Email alerts were working fine until I tried to be a bit more clever with the filters! Anyone else having this problem - and how was it fixed? Other services seem ok. It is very annoying as it was one of the main reasons I got my rabbit! Still no word from the support guys ...

Here is the message that appears ....
-----------------------------------------------------------------

type Rapport d'exception

message

description Le serveur a rencontré une erreur interne () qui l'a empêché de satisfaire la requête.

exception

javax.servlet.ServletException: Define tag cannot set a null value
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:848)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:781)
org.apache.jsp.FR.srv_005fmail_005ffull_jsp._jspService(org.apache.jsp.FR.srv_005fmail_005ffull_jsp:1027)
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:322)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:291)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1063)
org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:386)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:229)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1063)
org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:386)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:229)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

cause mère

javax.servlet.jsp.JspException: Define tag cannot set a null value
org.apache.struts.taglib.bean.DefineTag.doEndTag(DefineTag.java:236)
org.apache.jsp.FR.srv_005fmail_005ffull_jsp._jspService(org.apache.jsp.FR.srv_005fmail_005ffull_jsp:542)
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:322)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:291)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1063)
org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:386)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:229)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1063)
org.apache.struts.action.RequestProcessor.processForwardConfig(RequestProcessor.java:386)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:229)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

note La trace complète de la cause mère de cette erreur est disponible dans les fichiers journaux de Apache Tomcat/5.5.9.

You should trying to clear your cookies before login.

thanks but that clearing the cookies did not work. Also tried on another PC and get the same error. Email alerts had been working - then I was messing around tryign to setup filters, got the error and its never worked since. Clicking on Live Services shows that I have no email alert service setup. My thoughts are that in trying to setup my email alert filters somehow the data stored on the server (somewhere!) has become corrupted ... emailed the support team but no news ....