rem: var os = Components.classes["@mozilla.org/observer-service;1"].getService(Components.interfaces.nsIObserverService); 
add: var os = Components.classes["@mozilla.org/observer-service;1"] .getService(Components.interfaces.nsIObserverService); 
context:   uninit: function ()  {    var os = Components.classes["@mozilla.org/observer-service;1"].getService(Components.interfaces.nsIObserverService);    os.removeObserver(this, "Migration:Started");    os.removeObserver(this, "Migration:ItemBeforeMigrate");    os.removeObserver(this, "Migration:ItemAfterMigrate");    os.removeObserver(this, "Migration:Ended");  },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/a9d4c4716754e5e12c7b59a98f8f9ca3fb676845/migration.js/buggy/browser/components/migration/content/migration.js