.htaccess文件无法在服务器上运行

I have a URL like this

www.subdomain.mydomain.com/mydir/admin/index.php?page=dashboard

I want to have a user friendly url like this

www.subdomain.mydomain.com/mydir/admin/dashboard

How do I achieve this? I am trying with the below mentioned code. What am I doing wrong here?

Options -MultiViews

# URL rewriting module activation
RewriteEngine on
RewriteCond %{REQUEST_METHOD} !^(TRACE|TRACK|GET|POST|HEAD)$
RewriteRule .* - [F]
RewriteBase /
Options +FollowSymLinks


RewriteRule ^([a-zA-Z0-9_-]+)$ index.php?page=$1 [L]

For a similar context please refer this question.

Try this .htaccess:

Options +FollowSymLinks -MultiViews   
RewriteEngine on

# use appropriate rewrite base
RewriteBase /mydir/admin/

RewriteCond %{REQUEST_METHOD} !^(TRACE|TRACK|GET|POST|HEAD)$
RewriteRule ^ - [F]

RewriteCond %{THE_REQUEST} /index\.php\?page=([\w-]+) [NC]
RewriteRule ^ %1?  [L,R]

RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([\w-]+)/?$ index.php?page=$1 [L,QSA]