Installation problem

[shinokada]

I get the following error when I run composer update.

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

[RuntimeException]
Error Output: PHP Fatal error: Uncaught ReflectionException: Cla
ss log does not exist in /Users/sokada/Code/laravelpanel/vendor/l
aravel/framework/src/Illuminate/Container/Container.php:734
Stack trace:
#0 /Users/sokada/Code/laravelpanel/vendor/laravel/framework/src/I
lluminate/Container/Container.php(734): ReflectionClass->__constr
uct('log')
#1 /Users/sokada/Code/laravelpanel/vendor/laravel/framework/src/I
lluminate/Container/Container.php(629): Illuminate\Container\Cont
ainer->build('log', Array)
#2 /Users/sokada/Code/laravelpanel/vendor/laravel/framework/src/I
lluminate/Foundation/Application.php(697): Illuminate\Container\C
ontainer->make('log', Array)
#3 /Users/sokada/Code/laravelpanel/vendor/laravel/framework/src/I
lluminate/Container/Container.php(849): Illuminate\Foundation\App
lication->make('log')
#4 /Users/sokada/Code/laravelpanel/vendor/laravel/framework/src/I
lluminate/Container/Container.php(804): Illuminate\Container\Cont
ainer->resolveClass(Object(ReflectionParameter))
#5 /Users/sokada/Code/laravelpanel/vendor/laravel/framework/src/I
in /Users/sokada/Code/laravelpanel/vendor/laravel/framework/src/
Illuminate/Container/Container.php on line 734