rem: this.update.QueryInterface(Components.interfaces.nsIWritablePropertyBag); 
add: if (this.update) this.update.QueryInterface(Components.interfaces.nsIWritablePropertyBag); 
context:   setUpdate: function(update) {    this.update = update;    this.update.QueryInterface(Components.interfaces.nsIWritablePropertyBag);  },
meta: 7628	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/7628/0cc1ae114e84aa92106cf8f89da1ecd3a1bb09b7/updates.js/buggy/content/updates.js