nginx + apache problème avec le port 443

Voici ma configuration nginx pour le port 443 :

server {
    listen           *:443;
    server_name      site.com;

    ssl         on;
    ssl_protocols       SSLv3 TLSv1;
    ssl_certificate     /www/certs/site.com.crt;
    ssl_certificate_key /www/certs/site.com.key;

     access_log /var/log/nginx.site.com-access_log;
    location ~* .(jpg|jpeg|gif|png|css|zip|tgz|gz|rar|bz2|doc|xls|exe|pdf|ppt|tar|wav|bmp|rtf|swf|ico|flv|txt|xml|docx|xlsx)$ {
        root /www/site.com/;
        index index.html index.php;
        access_log off;
        expires 30d;
    }
    location ~ /.ht {
        deny all;
    }
    location / {
        proxy_pass http://127.0.0.1:81/;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-for $remote_addr;
        proxy_set_header Host $host;
        proxy_connect_timeout 60;
        proxy_send_timeout 90;
        proxy_read_timeout 90;
        proxy_redirect off;
        proxy_set_header Connection close;
        proxy_pass_header Content-Type;
        proxy_pass_header Content-Disposition;
        proxy_pass_header Content-Length;
    }
}

Question 1 : Pourquoi me demande-t-on d'entrer un pass PEM dans le certificat ? Comment puis-je envoyer le mot de passe dans la configuration de nginx ?

178-162-174-212:/usr/bin# service apache2 restart
Restarting web server: apache2.

178-162-174-212:/usr/bin# service nginx restart
Restarting nginx: Enter PEM pass phrase:
Enter PEM pass phrase:
[emerg]: bind() to 188.72.245.198:443 failed (98: Address already in use)
[emerg]: bind() to 188.72.245.198:443 failed (98: Address already in use)
[emerg]: bind() to 188.72.245.198:443 failed (98: Address already in use)
[emerg]: bind() to 188.72.245.198:443 failed (98: Address already in use)
[emerg]: bind() to 188.72.245.198:443 failed (98: Address already in use)
[emerg]: still could not bind()
nginx.

Question 2 : Pourquoi y a-t-il un conflit sur le port 443 ?

Configuration d'Apache :

NameVirtualHost *:81
Listen 127.0.0.1:81
Listen 999

<IfModule mod_ssl.c>
    Listen 443
</IfModule>

<IfModule mod_gnutls.c>
    Listen 443
</IfModule>

Si je commente la ligne "Listen 443", le site.com:443 ne fonctionne pas.