CodeIgniter Error - Undefined property: CI_Input::$post

[evilfreak]

I'm new to CodeIgniter and am trying to use the conditional below to determine whether or not the form has been submitted, and then display a certain view if it has. I got the error in the title for some reason and have been troubleshooting the problem for more than half and hour. Does anybody know how I might go about solving this problem? Thanks! \[code\]if($this->input->post->lastName){ // load view if form was submitted} else { // load other view}\[/code\]