Try removing the

use Controller;

statement on the top of the BaseController class and replace it with

use Illuminate\Routing\Controller;

It should look like this:

<?php namespace MyCompany\MyProject\Controllers;
// full file name: src/backend/MyCompany/MyProject/Controllers/BaseController.php

use Illuminate\Routing\Controller;
use View;
class BaseController extends Controller
{
	protected function setupLayout()
	{
		if (!is_null($this->layout)) {
			$this->layout = View::make($this->layout);
		}
	}
}

Or just remove the use statement all together if the Controller class your extending is within that namespace.

The easiest way to solve this problem is to add the following to the aliases array in config/app.php:

'Controller' => 'Illuminate\Routing\Controller',