NGINX reading cached html file shows special character on web page

Question

Modified nginx.conf and it works fine.

#user       nobody;
worker_processes  5;  ## Default: 1
error_log  logs/error.log;
pid        logs/nginx.pid;
worker_rlimit_nofile 8192;

events {
    worker_connections  1024;
}


http {
    include     mime.types;    
    include     fastcgi.conf;
    #include     koi-utf;
    #include    koi-win;
    index   cache.html cache.htm cache.php;


    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
            '$status $body_bytes_sent "$http_referer" '
            '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  logs/access.log  main;

    sendfile        on;
    tcp_nopush     on;

    server_names_hash_bucket_size 128;

    #keepalive_timeout  0;
    #keepalive_timeout  65;

    gzip  on;

    ######## additional Gun-zip configurations start #########
    gzip_http_version 1.1;
    gzip_vary on;
    gzip_comp_level 6;
    gzip_proxied any;
    #gzip_types text/plain text/html text/css application/json application/javascript application/x-javascript text/javascript text/xml application/xml application/rss+xml application/atom+xml application/rdf+xml;

    # make sure gzip does not lose large gzipped js or css files
    # see http://blog.leetsoft.com/2007/07/25/nginx-gzip-ssl.html
    gzip_buffers 16 8k;

    # Disable gzip for certain browsers.
    gzip_disable “MSIE [1-6].(?!.*SV1)”;
    ######## additional Gun-zip configurations end #########

    server {
        listen       88;
        server_name  localhost; 
        access_log  logs/host.access.log  main;

        access_log  logs/host.access.log  main;

        # proxy module defaults
        proxy_store_access   user:rw  group:rw  all:r;
        proxy_set_header  X-Real-IP  $remote_addr;
        proxy_set_header  Host       $host;

        #charset utf-8;
        #charset windows-1251;
        #source_charset koi8-r;

        # serve static files
        #location ~ ^/(images|javascript|js|css|flash|media|static)/  {
        #   root    D:/docroot/nginx/static/;
        #   expires 30d;
        #}

        # Main location
        location / {

            include     proxy.conf;
            root D:/docroot/ngnix/;
            index index.html index.htm;

            set $prefix  prefix_;

            # Use this if you don't cache a context (dont_cache_path) , send all requests through the proxy
            #location ~ ^/dont_cache_path {
            #   proxy_pass http://localhost:8080;
            #}

            # if the request uri was a directory, store the index page name
            if ($request_uri ~ /$) {
                set $store_extra index;
            }

            # set the location the proxy will store the data to. Add the index page
            # name if the uri was a directory (nginx can't normally store these)
            proxy_store D:/docroot/ngnix/${request_uri}${store_extra}.html;

            # go through the proxy if there is no cache
            if (!-f D:/docroot/ngnix/${request_uri}${store_extra}.html) {
                proxy_pass http://192.168.2.201:80;
            }

            # workaround. headers module doesn't take into account proxy response
            # headers. It overwrites the proxy Cache-Control header, causing
            # private/no-cache/no-store to be wiped, so only set if not using proxy
            #if (-f  D:/docroot/ngnix/${request_uri}${store_extra}.html) {
            #   expires 0;
            #}

            # handle static files directly. Set their expiry time to max, so they'll
            # always use the browser cache after first request
            location ~* (css|js|png|jpe?g|gif|ico|swf)$ {
                root D:/docroot/;
                expires max;
            }
        }

        #error_page  404              /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }

    }

}

NGINX reading cached html file shows special character on web page

I'm using NGINX 1.4.4 with APACHE 2.2. NGINX creates cache file but when shame page is requested, cached file is read by NGINX and displays. Problem is the cached file contents are displayed as encoded characters on the web page. Following is my nginx.conf configuration.

Following is koi-utf file

With first request it works proper as the response is from apache web server. When I re-request it reads cached page which looks like the below.

What is causing this problem? Please, correct me if my configuration is wrong.