After updating to Firefox 17.0.1 PrivilegeManager is no longer supported. Various sources say, it is yet possible to simply remove the respective line from the code and everything should work just fine. Unfortunately this is not the case here.
I always get an error: TypeError: Components.classes is undefined. Are there changes concerning Components.classes as well? The Mozilla Code Snippets page (https://developer.mozilla.org/en-US/docs/Code_snippets/File_I_O) states the same syntax (without using FileUtils.jsm).
My code:
//netscape.security.PrivilegeManager.enablePrivilege('UniversalXPConnect');
var file = Components.classes["@mozilla.org/file/local;1"]
.createInstance(Components.interfaces.nsILocalFile);
file.initWithPath(filePath);