title: PHP Fatal error: Class 'PDO' not found using laravel4
body: <p>After one hour tring to solve this problem I failed ): my error message is :</p>
  
  <pre><code>Generating autoload files
  PHP Fatal error:  Class 'PDO' not found in /usr/share/nginx/html/laravel/app/config/database.php on line 16
  {"error":{"type":"Symfony\\Component\\Debug\\Exception\\FatalErrorException","message":"Class 'PDO' not found","file":"\/usr\/share\/nginx\/html\/laravel\/app\/config\/database.php","line":16}}Script php artisan clear-compiled handling the post-update-cmd event returned with an error
  
  
  
    [RuntimeException]                                                                                                    
    Error Output: PHP Fatal error:  Class 'PDO' not found in /usr/share/nginx/html/laravel/app/config/database.php on li  
    ne 16                                                                                                                 
  
  
  
  
  update [--prefer-source] [--prefer-dist] [--dry-run] [--dev] [--no-dev] [--lock] [--no-plugins] [--no-custom-installers] [--no-scripts] [--no-progress] [--with-dependencies] [-v|vv|vvv|--verbose] [-o|--optimize-autoloader] [packages1] ... [packagesN]
  </code></pre>
  
  <p>I am using linux centos 6.4 php 5.5.3 and laravel 4.</p>
  
  <p>Could you help me thanks very much.</p>