Script php artisan clear-compiled handling the pre-update-cmd event returned with an error (Laravel 4.1 upgrade)

Maybe you can try this command:

composer install --no-scripts

Did you follow the upgrade procedure? Running composer update won't be enough. laravel.com/docs/upgrade

Try to remove /bootstrap/compiled.php (I was in trouble downgrading Laravel 4.2 > 4.1)

Then try to composer update, it should work.

Good luck