nginx 1.6.2 [Windows] won't find protected directory - html

Question

as the headline said, my nginx isn't able to find .htpasswd-protected directories. Here are my settings, my .conf and the locations of the relevant files:
NOTE: due to my brothers wish, the nginx runs on a win8.1x32 virtual machine
I created a .htaccess file in my root/xx directory looking like this:
AuthName "Restricted Area"
AuthType Basic
AuthUserFile /b/.htpasswd
AuthGroupFile /dev/null
require valid-user
And I created a .htpasswd file inside the shown directory.
After that I modified my .conf in the conf-folder like this:
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
server {
listen 80;
server_name localhost;
location / {
root html;
index index.html index.htm;
}
location ^~ /b/ {
auth_basic "Restricted Area";
auth_basic_user_file b/htpasswd;
}
}
I deleted the comment-lines from the auto-generated file only here, in the original, they are still existent - thought this might clear your sight on the file.
Now, here comes the problem: the file which I am aiming for is called int.html and can be found in /b/int.html (stylesheets and scriptfiles included), but every time i want to get to this file, the browser asks my to type in password and username - as I wanted it - but then the browser shows a 404-error, which means, he couldn't find the named file. (I made sure everything is spelled correct in the directories and tried this in several browsers on different devices). I don't know why. (I already tried to set the int.html as index in the config like this:
location ^~ /b/ {
auth_basic "Restricted Area";
auth_basic_user_file b/htpasswd;
}
But it still doesn't work. - Ideas, anyone?
Greetz Dyarn