rem: this.throbber.setAttribute("busy", false); 
add:  if (this.throbber) this.throbber.setAttribute("busy", false); 
context:    _stopMeteors : function()    {      if(gTimelineEnabled){        gTimelineService.stopTimer("FolderLoading");        gTimelineService.markTimer("FolderLoading");        gTimelineService.resetTimer("FolderLoading");      }      this.ensureStatusFields();      var msg = gMessengerBundle.getString("documentDone");      this.showStatusString(msg);      defaultStatus = msg;      this.throbber.setAttribute("busy", false);      // Turn progress meter off.      this.statusBar.setAttribute("mode","normal");      this.statusBar.value = 0;  // be sure to clear the progress bar      this.statusBar.label = "";      this.stopCmd.setAttribute("disabled", "true");      this.meteorsSpinning = false;      this.stopTimeoutID = null;    },
meta: 5872	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5872/26e84c6e9330b25a72f791d7f81880f785be948a/mailWindow.js/clean/mailnews/base/resources/content/mailWindow.js