Symphony.

I placed a folder called diplome in the root of the site clubulmontanaltitudine.mcas.ro. When I try to access the folder, I get a 403 redirect from the browser.

Any ideas what's going on?

Here's the links that should list the contents of the folder:

http://clubulmontanaltitudine.mcas.ro/diplome/

I'd go ahead and debug the mod_rewrite procedure

Is this a Symphony site?

If so, then it should work fine as Symphony's rewrite rules ignore physical folders. If not then you need to go and ask on Stack Overflow or similar.

Of course it's a Symphony site :)

it should work fine as Symphony's rewrite rules ignore physical folders

It's rather strange. I have other sites where accessing subfolders works fine. Dunno what's happening in this case.

How can I check if the folder has the correct permissions?

In terminal, in the parent folder run ls -la

That'll show you what permissions are on the folder.