newbie: Internal Server Error

Giganews Newsgroups
Subject: newbie: Internal Server Error
Posted by:  Jivanmukta (jivanmuk…
Date: Mon, 9 May 2011

I created website in C:\Program Files\wamp\www\og=C5=82oszenia-
nieruchomo=C5=9Bci. When I try to open it using http://localhost/og=C5=82os=
I receive the following error:

Internal Server Error
The server encountered an internal error or misconfiguration and was
unable to complete your request.
Please contact the server administrator, admin@localhost and inform
them of the time the error occurred, and anything you might have done
that may have caused the error.
More information about this error may be available in the server error

There's nothing concerning my problem in error.log.
Here is my .htaccess:

ErrorDocument 401 "C:\Program Files\wamp\www\og=C5=82oszenia-nieruchomo=C5=
AuthUserFile "C:\Program Files\wamp\www\og=C5=82oszenia-nieruchomo=C5=9Bci
AuthName "Strony zabezpieczone"
AuthType Basic
require valid-user
RewriteEngine on
RewriteCond %{HTTP_HOST} ^$ [NC,OR]
RewriteCond %{HTTP_HOST} ^$ [NC]
RewriteRule ^(.*)$ not_found.php [L]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .* index.html [L]

The files denial.html and .htpass are valid.
Please help.