Extending CI with own library

Answer 1

Your controller needs a constructor. It should look like this:

class Timevalueshow extends Controller{

    function __construct(){
        parent::__construct();
        $params = array('years' => 0, 
            'rate' => 0, 
            'principle' => 0, 
            'periods' => 0, 
            'isCont' => true
        );
        $this->load->library('timevalue',$params);
    }

    function index(){       
        $this->load->view('Timevalueshow_view');
    }
}

Only PHP5 uses the __construct function. In PHP4 it should look like this:

function Timevalueshow(){
    parent::Controller();
}