Error 500 (Internal Server Error) when uploading

When trying to upload a txt file, I'm getting erro 500 .

I gave # chmod -R 777 import to release all permissions. < ls -l of the folder where I am trying to save the file:

  

drwxrwxrwx 2 francisco francisco 4096 Dec 2 12:28 PM import

My Yii is set to use URL-Amigável :

'urlManager' => array(
    'urlFormat' => 'path',
    'rules' => array(
        '<controller:\w+>/<id:\d+>' => '<controller>/view',
        '<controller:\w+>/<action:\w+>/<id:\d+>' => '<controller>/<action>',
        '<controller:\w+>/<action:\w+>' => '<controller>/<action>',
    ),
),

And Nginx is also configured:

server {

    client_max_body_size 20M;

    listen 127.0.2.1:80;
    listen 192.168.25.33:80;
    root    /usr/share/nginx/meudominio.com;
    index index.php;

    server_name local.meudominio.com;

    location / {
        index index.php;
        try_files $uri $uri/ /index.php?$args;
    }

    location ~ ^/(app|framework|themes/\w+/views){
        deny all;
    }

    location ~ \.(js|css|png|jpg|gif|swf|ico|pdf|mov|fla|zip|rar)$ {
        try_files $uri =404;
    }

    location ~ \.php$ {
        fastcgi_pass unix:/var/run/php5-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
    }
}