Update

[eluser]PhilTem[/eluser]
[quote author="TWP Marketing" date="1343071149"]Isn't this error caused by the same class name in application/libraries and in application/helpers?

When you remove the library file 'Locale.php', it may need a cache flush.[/quote]

You have classes in your application/helpers? You shouldn't have. The helpers are supposed to be functions that can be called and not methods of classes.
Or I got your point wrong