[eluser]Aken[/eluser]
Are you loading the Email library anywhere else - in the controller constructor or autoload? The library itself will not throw this error on its own - you have to be passing something invalid for it somewhere, or you have something corrupted, or some third-party code is causing it...
Try creating a new controller and load the Email library and see what happens. If it works, then you can narrow down your code a bit.
