You need to also make sure you changed AllowOverride None
to AllowOverride All
in your httpd.conf file wherever you find it.
Try doing it this way.
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^page/(.+)/?$ /?cmd=$1 [NC,L]