Installing and upgrading help

Hello!
I need help with installing Moodle on my dedicated Ubuntu 14.04 server.
On it I have my Joomla 2.5, 3.0 websites and BigBlueButton (BBB), all of which run flawlessly on the server.
My websites run on nginx, since BBB requires it.
I've tried setting up Apache2 + nginx, but somehow this setup doesn't want to work properly, so I'm using nginx only.

Any help will be appreciated, since I'm out of ideas and my hosting support is basically useless.

The goal

I'm transferring my websites from a VPS hosting to a Dedicated server.
Since Joomla works fine, I need to make sure that Moodle does as well.
Before transferring the main domain, I need to test a copy of the Moodle website on my test domain.

The issue

After uploading the website copy I check the result only to see a "naked" html page without css. (img.1)
Which is strange, because, like I said, my other websites work fine. 

So I decided to upload a blank Moodle, for a clean install.
The first few pages of the installation were fine, the css was present.
After the Server Checks page I'm redirected to a blank installation page. 
The page remained static, even after an hour of waiting.

Restarting the page corrupts the installation, which may be the reason for the missing css.
BUT! If I swap nginx for apache2, the css is displayed normally.

Installing with Apache2

So I decided to install Moodle with apache2 running instead of nginx. 
Everything went smooth, I even got to see the Installation page and a gradually growing list of installed plugins.
Then the installation process froze on the auth_mnet plugin.
I waited for a descent amount of time, before reloading the page.
After the reload I was redirected to the Plugin check page where I clicked Update Moodle database.
The rest of the installation process went as it should and I got my moodle page, which had css.
Though the page content was only covering the left half of the page (img. 2)

Since everything installed correctly I swapped everything back to nginx.
But all I get is that naked page... (img. 1)

Nginx sites-available settings for the domain

server {
 listen   80; 
 ## listen for ipv4; this line is default and implied	
 #listen   [::]:80 default ipv6only=on; ## listen for ipv6
 #root /var/www/skypespanol;
 root /var/www/scoolcom/data/www/skypespanol.ru;
	
 index index.html index.htm;
			
 # Make site accessible from http://localhost/
 server_name skypespanol.ru www.skypespanol.ru;
		
 location ~ \.php$ {			
  try_files $uri /index.php =404;				
  fastcgi_pass unix:/var/run/php5-fpm.sock;				
  fastcgi_index index.php;				
  fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;			
  include fastcgi_params;
 }	
	
 location / {							
  autoindex on;			
  index index.php index.html index.htm;			
  # try_files $uri $uri/ /public/index.php$request_uri;		
  try_files $uri $uri/ $uri/index.php;
 }
}

Images

img. 1

img. 2