rem: var uri = Components.classes["@mozilla.org/network/io-service;1"] .getService(Components.interfaces.nsIIOService) .newFileURI(aFile); 
add: var uri = Cc["@mozilla.org/network/io-service;1"]. getService(Ci.nsIIOService).newFileURI(aFile); 
context: function openExternal(aFile){  var uri = Components.classes["@mozilla.org/network/io-service;1"]                      .getService(Components.interfaces.nsIIOService)                      .newFileURI(aFile);  var protocolSvc =       Components.classes["@mozilla.org/uriloader/external-protocol-service;1"]                .getService(Components.interfaces.nsIExternalProtocolService);  protocolSvc.loadUrl(uri);  return;}
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/8395/43455f9fc69a7b8e33dae13cc90fd333fc5448d2/downloads.js/buggy/toolkit/mozapps/downloads/content/downloads.js