Clicking the platform link in auto discovery portlet which has IP Set change update gives following NPE in UI. No errors in server log.

java.lang.NullPointerException
    at org.hyperic.hq.ui.util.BizappUtils$AIResourceIdComparator.compare(BizappUtils.java:443)
    at java.util.TreeMap.compare(Unknown Source)
    at java.util.TreeMap.put(Unknown Source)
    at java.util.TreeSet.add(Unknown Source)
    at java.util.AbstractCollection.addAll(Unknown Source)
    at java.util.TreeSet.addAll(Unknown Source)
    at org.hyperic.hq.ui.util.BizappUtils.sortAIResource(BizappUtils.java:462)
    at org.hyperic.hq.ui.action.resource.platform.autodiscovery.ViewResultsPrepAction.workflow(ViewResultsPrepAction.java:130)
    at org.hyperic.hq.ui.action.WorkflowPrepareAction.execute(WorkflowPrepareAction.java:79)
    at org.apache.struts.tiles.actions.TilesAction.execute(TilesAction.java:73)
    at org.hyperic.hq.ui.action.BaseRequestProcessor.processActionPerform(BaseRequestProcessor.java:63)
    at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
    at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
    at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:697)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:672)
    at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:574)
    at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:499)
    at org.apache.struts.tiles.UrlController.execute(UrlController.java:89)
    at org.apache.struts.taglib.tiles.InsertTag$InsertHandler.doEndTag(InsertTag.java:875)
    at org.apache.struts.taglib.tiles.InsertTag.doEndTag(InsertTag.java:462)
    at org.apache.jsp.portal.ColumnsLayout_jsp._jspx_meth_tiles_insert_0(Unknown Source)
    at org.apache.jsp.portal.ColumnsLayout_jsp._jspx_meth_c_forEach_1(Unknown Source)
    at org.apache.jsp.portal.ColumnsLayout_jsp._jspx_meth_c_forEach_0(Unknown Source)
    at org.apache.jsp.portal.ColumnsLayout_jsp._jspService(Unknown Source)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:672)
    at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:574)
    at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:499)
    at org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:966)
    at org.apache.jasper.runtime.PageContextImpl.include(PageContextImpl.java:604)
    at org.apache.struts.tiles.TilesUtilImpl.doInclude(TilesUtilImpl.java:99)
    at org.apache.struts.tiles.TilesUtil.doInclude(TilesUtil.java:135)
    at org.apache.struts.taglib.tiles.InsertTag.doInclude(InsertTag.java:760)
    at org.apache.struts.taglib.tiles.InsertTag$InsertHandler.doEndTag(InsertTag.java:892)
    at org.apache.struts.taglib.tiles.InsertTag.doEndTag(InsertTag.java:462)
    at org.apache.jsp.portal.MainLayout_jsp._jspx_meth_tiles_insert_3(Unknown Source)
    at org.apache.jsp.portal.MainLayout_jsp._jspx_meth_html_html_0(Unknown Source)
    at org.apache.jsp.portal.MainLayout_jsp._jspService(Unknown Source)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:672)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:463)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:398)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:301)
    at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1085)
    at org.apache.struts.tiles.TilesRequestProcessor.doForward(TilesRequestProcessor.java:263)
    at org.apache.struts.tiles.TilesRequestProcessor.processTilesDefinition(TilesRequestProcessor.java:239)
    at org.apache.struts.tiles.TilesRequestProcessor.internalModuleRelativeForward(TilesRequestProcessor.java:341)
    at org.apache.struts.action.RequestProcessor.processForward(RequestProcessor.java:572)
    at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:221)
    at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
    at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:697)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
    at org.hyperic.hq.ui.AuthenticationFilter.doFilter(AuthenticationFilter.java:153)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
    at org.hyperic.hibernate.filter.SessionFilter$1.run(SessionFilter.java:59)
    at org.hyperic.hq.hibernate.SessionManager.runInSessionInternal(SessionManager.java:79)
    at org.hyperic.hq.hibernate.SessionManager.runInSession(SessionManager.java:68)
    at org.hyperic.hibernate.filter.SessionFilter.doFilter(SessionFilter.java:57)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
    at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:81)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
    at org.hyperic.hq.product.servlet.filter.JMXFilter.doFilter(JMXFilter.java:324)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
    at org.jboss.web.tomcat.security.CustomPrincipalValve.invoke(CustomPrincipalValve.java:39)
    at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:159)
    at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:59)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:744)
    at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
    at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
    at java.lang.Thread.run(Unknown Source)