Hi, I´m a new user and have the following question:
I downloaded, unstalled and re-installed Zimbra Desktop 3 times, but I was unable to start Zimbra Desktop and received the following Error-message:
HTTP ERROR: 500

org.apache.xerces.dom.DeferredDocumentImpl.setDocu mentURI(Ljava/lang/StringV

RequestURI=/zimbra/desktop/login.jsp
Caused by:

java.lang.AbstractMethodError: org.apache.xerces.dom.DeferredDocumentImpl.setDocu mentURI(Ljava/lang/StringV
at org.apache.jasper.xmlparser.ParserUtils.par***MLDo cument(ParserUtils.java:226)
at org.apache.jasper.compiler.JspConfig.processWebDot Xml(JspConfig.java:123)
at org.apache.jasper.compiler.JspConfig.init(JspConfi g.java:295)
at org.apache.jasper.compiler.JspConfig.findJspProper ty(JspConfig.java:360)
at org.apache.jasper.compiler.Compiler.generateJava(C ompiler.java:141)
at org.apache.jasper.compiler.Compiler.compile(Compil er.java:398)
at org.apache.jasper.JspCompilationContext.compile(Js pCompilationContext.java:592)
at org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:344)
at org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:477)
at org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:371)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:820)
at com.zimbra.webClient.servlet.JspServlet.service(Js pServlet.java:50)
at org.mortbay.jetty.servlet.ServletHolder.handle(Ser vletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler.handle(Se rvletHandler.java:362)
at org.mortbay.jetty.security.SecurityHandler.handle( SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(Se ssionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(Co ntextHandler.java:716)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebA ppContext.java:406)
at org.mortbay.jetty.servlet.Dispatcher.forward(Dispa tcher.java:268)
at org.mortbay.jetty.servlet.Dispatcher.forward(Dispa tcher.java:126)
at org.apache.jasper.runtime.PageContextImpl.forward( PageContextImpl.java:767)
at org.apache.jsp.desktop.login_jsp._jspx_meth_c_when _0(login_jsp.java:423)
at org.apache.jsp.desktop.login_jsp._jspx_meth_c_choo se_0(login_jsp.java:390)
at org.apache.jsp.desktop.login_jsp._jspService(login _jsp.java:246)
at org.apache.jasper.runtime.HttpJspBase.service(Http JspBase.java:93)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:820)
at org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:373)
at org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:477)
at org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:371)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:820)
at com.zimbra.webClient.servlet.JspServlet.service(Js pServlet.java:50)
at org.mortbay.jetty.servlet.ServletHolder.handle(Ser vletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler$CachedCha in.doFilter(ServletHandler.java:1093)
at com.zimbra.webClient.filters.SetHeaderFilter.doFil ter(SetHeaderFilter.java:265)
at org.mortbay.jetty.servlet.ServletHandler$CachedCha in.doFilter(ServletHandler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle(Se rvletHandler.java:360)
at org.mortbay.jetty.security.SecurityHandler.handle( SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(Se ssionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(Co ntextHandler.java:716)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebA ppContext.java:406)
at org.mortbay.jetty.handler.ContextHandlerCollection .handle(ContextHandlerCollection.java:211)
at org.mortbay.jetty.handler.HandlerCollection.handle (HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(Ha ndlerWrapper.java:139)
at org.mortbay.jetty.handler.RewriteHandler.handle(Re writeHandler.java:176)
at org.mortbay.jetty.handler.HandlerWrapper.handle(Ha ndlerWrapper.java:139)
at org.mortbay.jetty.Server.handle(Server.java:313)
at org.mortbay.jetty.HttpConnection.handleRequest(Htt pConnection.java:506)
at org.mortbay.jetty.HttpConnection$RequestHandler.he aderComplete(HttpConnection.java:830)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser. java:514)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpPa rser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnec tion.java:381)
at org.mortbay.io.nio.SelectChannelEndPoint.run(Selec tChannelEndPoint.java:396)
at org.mortbay.thread.BoundedThreadPool$PoolThread.ru n(BoundedThreadPool.java:442)

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Please, who is able to give me an advice!

Thank You very much!
haraldo