rem: return aHandlerApp.executable && aHandlerApp.executable.exists() && aHandlerApp.executable.isExecutable(); 
add: return this._isValidHandlerExecutable(aHandlerApp.executable); 
context:   isValidHandlerApp: function(aHandlerApp) {    if (!aHandlerApp)      return false;    if (aHandlerApp instanceof Ci.nsILocalHandlerApp)      return aHandlerApp.executable &&             aHandlerApp.executable.exists() &&             aHandlerApp.executable.isExecutable();    if (aHandlerApp instanceof Ci.nsIWebHandlerApp)      return aHandlerApp.uriTemplate;    if (aHandlerApp instanceof Ci.nsIWebContentHandlerInfo)      return aHandlerApp.uri;    return false;  },
meta: 10520	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/10520/94ac7e3ed893d5c96bfe8d6a286fd35874168554/applications.js/buggy/browser/components/preferences/applications.js