Laravel 4.2 artisan CLI does not work anymore after composer update

问题

I just ran "composer update" on my production server, and received this error:

Script php artisan clear-compiled handling the post-update-cmd event returned with an error

When I try any "php artisan" commands, I do not receive any results.

I have tried deleting my composer.lock file and my vendor folder, and ran "composer install" again, but no results.

Here is my composer.json file:

{
"name": "laravel/laravel",
"description": "The Laravel Framework.",
"keywords": ["framework", "laravel"],
"license": "MIT",
"type": "project",
"require": {
"laravel/framework": "4.2.*",
"bllim/laravalid": "dev-laravel4",
"facebook/php-sdk-v4" : "~5.0" 

},
"autoload": {
"classmap": [
"app/commands",
"app/controllers",
"app/composers",
"app/models",
"app/database/migrations",
"app/database/seeds",
"app/tests/TestCase.php"
]
},
"scripts": {
"post-install-cmd": [
"php artisan clear-compiled",
"php artisan optimize"
],
"post-update-cmd": [
"php artisan clear-compiled",
"php artisan optimize"
],
"post-create-project-cmd": [
"php artisan key:generate"
]
},
"config": {
"preferred-install": "dist"
},
"minimum-stability": "stable"
}

My production server runs PHP 5.6 and Apache 2.4.