Have you added the remember_token to your migration? Look at my migration for the users:

<?php

use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateUsersTable extends Migration {

	/**
	 * Run the migrations.
	 *
	 * @return void
	 */
	public function up()
	{
		Schema::create('users', function(Blueprint $table)
		{
			$table -> increments('id');

			$table -> string('name', 32);
			$table -> string('email', 320);
			$table -> string('password', 64);
			$table -> string('remember_token', 100) -> nullable();

			$table -> timestamps();
		});
	}

	/**
	 * Reverse the migrations.
	 *
	 * @return void
	 */
	public function down()
	{
		Schema::drop('users');
	}

}

Maybe you should also hide the token in your model:

protected $hidden = array(
		'password',
		'remember_token'
	);