NullPointerException in Tomcat when reloading page before it is downloaded completely:

"Caused by: java.lang.NullPointerException
  at org.apache.catalina.connector.Response.toAbsolute(Response.java:1485)
  at org.apache.catalina.connector.Response.sendRedirect(Response.java:1250)
  at org.apache.catalina.connector.ResponseFacade.sendRedirect(ResponseFacade.java:440)
  at com.icesoft.faces.webapp.http.servlet.ServletExternalContext$3.redirect(ServletExternalContext.java:260)
  at com.icesoft.faces.context.BridgeExternalContext.redirect(BridgeExternalContext.java:340)
  at com.sun.faces.application.NavigationHandlerImpl.handleNavigation(NavigationHandlerImpl.java:171)
  at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:119)
  at javax.faces.component.UICommand.broadcast(UICommand.java:383)
  at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:447)
  at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:752)
  at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:97)
  at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251)
  ... 29 more"