I'm unable to reproduce this problem when clicking through the sample app, but I am able to reproduce it when using WAPT (under semi high load).

java.lang.NullPointerException
       at net.sf.navigator.taglib.DisplayMenuTag.setLocation
(DisplayMenuTag.java:176)
       at net.sf.navigator.taglib.DisplayMenuTag.setPageLocation
(DisplayMenuTag.java:140)
       at net.sf.navigator.taglib.DisplayMenuTag.setPageLocation
(DisplayMenuTag.java:168)
       at net.sf.navigator.taglib.DisplayMenuTag.doStartTag
(DisplayMenuTag.java:92)
       at _jsp._index__jsp._jspService(index.jsp:26)
       at com.caucho.jsp.JavaPage.service(JavaPage.java:60)
       at com.caucho.jsp.Page.pageservice(Page.java:570)
       at com.caucho.server.dispatch.PageFilterChain.doFilter
(PageFilterChain.java:159)
       at com.caucho.server.webapp.WebAppFilterChain.doFilter
(WebAppFilterChain.java:163)
       at com.caucho.server.dispatch.ServletInvocation.service
(ServletInvocation.java:208)
       at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:
259)
       at com.caucho.server.port.TcpConnection.run(TcpConnection.java:363)
       at com.caucho.util.ThreadPool.runTasks(ThreadPool.java:490)
       at com.caucho.util.ThreadPool.run(ThreadPool.java:423)
       at java.lang.Thread.run(Thread.java:595)