Laravel MethodNotAllowedHttpException, but my methods match - php

Question

I have a registration form that I'm creating using the blade templating like so:
{{ Form::open(array('url'=>'registerUser', 'method'=>'POST', 'class'=>'loginForm SignUp')) }}
In routes.php, I have the following route:
Route::post('registerUser', 'UsersController#doRegister');
But when I submit the form, I get a MethodNotAllowedHttpException. Pretty much every other question I've found online about this was a case of the form having the GET method while the route had POST, but mine match, so I'm pretty confused.
Edit: Here's my full routes file:
Route::get('', 'UsersController#showLogin');
Route::get('login', 'UsersController#showLogin');
Route::post('doLogin', 'UsersController#doLogin');
Route::get('signUp', 'UsersController#showSignUp');
Route::post('authenticateCode', 'UsersController#authenticateCode');
Route::post('requestCode', 'UsersController#requestCode');
Route::get('showRegister', 'UsersController#showRegister');
Route::post('registerUser', 'UsersController#doRegister');
Route::get('dashboard', 'DashboardController#showDashboard');
Here's the controller function:
public function doRegister() {
$rules = array(
'fname' => 'required|alpha|min:2',
'lname' => 'required|alpha|min:2',
'email' => 'required|email|unique:users',
'phone' => 'required|alpha_num|min:7',
'company' => 'required|alpha_spaces|min:2',
'password' => 'required|alpha_num|between:6,12|confirmed', // these password rules need to be improved
'password_confirmation' => 'required|alpha_num|between:6,12'
);
$validator = Validator::make(Input::all(), $rules);
if($validator->passes()) {
$user = User::create(array(
'fname' => Input::get('fname'),
'lname' => Input::get('lname'),
'email' => Input::get('email'),
'password' => Hash::make(Input::get('password')),
'phone' => Input::get('phone'),
'company' => Input::get('company')
));
// Update the invite key that was passed to the register page
// with this new user's ID.
$key = InviteKey::find(Input::get('key'));
$key->user_id = $user->id;
$key->save();
return Redirect::to('login')->with('message', 'Thank you for registering!');
} else {
return Redirect::to('register')
->with('message', 'The following errors occurred')
->withErrors($validator)
->withInput(Input::except('password'));
}
}