how do you handle form submissions

[eluser]jvittetoe[/eluser]
this issue arises when i submit the form and call the dashboard/updateUserAccount...when it gets tothe else statement, these lines are throwing errors.

Code:

$password_old = $this->validation->password_old;
            $password_new = $this->validation->password_new;
            $password_conf = $this->validation->password_conf;
            $firstname = $this->validation->firstname;
            $lastname = $this->validation->lastname;

the errors are..
Message: Undefined property: password_old
Message: Undefined property: password_new
...and so on for all 5.

ive also updated my model function with your suggestion. but my script is failing before it even gets there.