403 Forbidden page when navigating to themes configuration

I cloned a fully working Omeka 2.4.1 installation from one server to another.
The cloned installation works almost fine, excepting for a one thing:
When I try to navigate to /admin/themes/ location to setup my theme, I get the 403 Forbidden message from the server (this is also visible in server logs).
I am able to setup the theme, getting to the theme configuration page directly from the admin menu “Appearance”. It links directly to the /admin/appearance page’s first tab, which is “Themes”.
But when I switch to another tab, let’s say “Navigation” and try to get back to the “Themes” tab, I get the 403 page after clicking on the “Themes”. This tab links to /admin/themes page which is unavailable for me.

This exercise works fine on the original source installation on a different server, so I guess there might be something wrong with the server configuration. But usually some wrong server configuration would make more things not to work properly. Meanwhile in my case all works good but this one thing.

I’ve already checked the directory and files access rights on the server and all are ok: both the installations (original and cloned) have the same rights.
I’ve also made a clean Omeka install on the destination server and the problem still exists.
I’ve also tried to comment out the whole “Access Control” section in .htaccess file but the problem still is.

Isn’t it strange, that the themes config page access is dependent on the navigating address: the admin/appearance works but the admin/themes does not?

I will appreciate some helpful remarks.

Could it be that one of the URLs you’re using has a trailing slash and one doesn’t?

Normally this doesn’t make any difference but it could be that the “with trailing slash” variant is being seen by Apache on your particular installation as pointing to the “real” themes folder in the installation, while the slashless variant that’s used in the Appearance settings navigation correctly routes through the Omeka index.php.

No matter if I use trailing slash or not.

I solved it by adding to the .htaccess the following:

Options +DirList

But I’m not sure yet, if it could make any potential security issue for the site?