_ibmjsp.secure.layouts NPE on WebSphere Adminisrative Console

I was trying to deploy an EAR file to a WebSphere Process Server instance. I went to the WebSphere Adminisrative Console, clicked on Applications, Enterprise Application, local file system, specify the path and clicked next, then another next when I got the following stacktrace:

java.lang.NullPointerException
 at _ibmjsp.secure.layouts._stepsLayout._jspService(_stepsLayout.java:581)
 at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:93)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
 at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1572)
 at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1521)
 at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:113)
 at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:82)
 at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:759)
 at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:121)
 at com.ibm.ws.jsp.webcontainerext.JSPExtensionServletWrapper.handleRequest(JSPExtensionServletWrapper.java:215)
 at com.ibm.ws.jsp.webcontainerext.JSPExtensionProcessor.handleRequest(JSPExtensionProcessor.java:255)
 at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.forward(WebAppRequestDispatcher.java:347)
 at org.apache.struts.action.RequestProcessor.doForward(RequestProcessor.java:1070)
 at org.apache.struts.tiles.TilesRequestProcessor.doForward(TilesRequestProcessor.java:273)
 at org.apache.struts.tiles.TilesRequestProcessor.processTilesDefinition(TilesRequestProcessor.java:253)
 at org.apache.struts.tiles.TilesRequestProcessor.processForwardConfig(TilesRequestProcessor.java:308)
 at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:279)
 at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1486)
 at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:528)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:763)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
 at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1572)
 at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1521)
 at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:136)
 at com.ibm.ws.console.core.servlet.WSCUrlFilter.continueStoringTaskState(WSCUrlFilter.java:311)
 at com.ibm.ws.console.core.servlet.WSCUrlFilter.doFilter(WSCUrlFilter.java:185)
 at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:142)
 at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:121)
 at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:82)
 at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:759)
 at com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:3177)
 at com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:253)
 at com.ibm.ws.webcontainer.VirtualHost.handleRequest(VirtualHost.java:229)
 at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:1970)
 at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:114)
 at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:472)
 at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewInformation(HttpInboundLink.java:411)
 at com.ibm.ws.http.channel.inbound.impl.HttpICLReadCallback.complete(HttpICLReadCallback.java:101)
 at com.ibm.ws.ssl.channel.impl.SSLReadServiceContext$SSLReadCompletedCallback.complete(SSLReadServiceContext.java:1704)
 at com.ibm.ws.tcp.channel.impl.WorkQueueManager.requestComplete(WorkQueueManager.java:566)
 at com.ibm.ws.tcp.channel.impl.WorkQueueManager.attemptIO(WorkQueueManager.java:619)
 at com.ibm.ws.tcp.channel.impl.WorkQueueManager.workerRun(WorkQueueManager.java:952)
 at com.ibm.ws.tcp.channel.impl.WorkQueueManager$Worker.run(WorkQueueManager.java:1039)
 at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1471)

The stacktrace was unexpected because I've done this installation before and I had no problem previously. The _ibmjsp.secure.layouts._stepsLayout._jspService was quite curious since it didn't seem to have anything to do with what I'm doing.
I went to my package ear file, clean my build environment, recreate the ear and try to redeploy it again. The same thing happened again. Check the log, puzzled, decide to restart the server just in case. Still no change. Reboot the dev box, hoping for the best. And yet nothing changed.
That _ibmjsp.secure.layouts message kept nagging on my mind. Could it be... And of course it is...
You see, all this time I was using Firefox to connect to the admin console and it's ok most of the time. I always got the security certificate warning, always ignore it and it's usually okay. I don't know what's change, but just to eliminates any potential difference, I open Internet Explorer (7), go to the console and try the app installation sequence and this time it works.
I don't have time to figure out what make the response different on firefox, I got the app deployed and that's all that matter for now.