A: 

.htaccess affects all directories underneath, so if you put an .htaccess in csNewsAd with the rewrite directives you want, it will take precedence over the root file.

songdogtech
A: 

you could add something like this:

RewriteCond %{REQUEST_URI} !^/csNewsAd 

but this should not be needed, because if csNewsAd indeed is a directory (folder) it should not be rewritten in the first place because of

RewriteCond %{REQUEST_FILENAME} !-d

are you sure there isn't anything else sitting between you and that folder, rights or (indeed) another .htaccess?

futtta
There's another .htaccess for password protection. I'll add the code to the question.
Joel Alejandro
A: 

If you’re using mod_rewrite in a .htaccess file, you just need to specify the URL path without the local path prefix in your patterns. In your case without the leading / (as you’re in the document root /):

RewriteRule ^csNewsAd($|/) - [L]
Gumbo
Still without working.
Joel Alejandro
@Joel Alejandro: Did you replace your other rule with the leading `/`?
Gumbo
Yes, no changes.
Joel Alejandro
A: 

RewriteCond %{REQUEST_URI} !^/(csNewsAd|csNewsAd/.*)$

instead of

RewriteRule ^/csNewsAd($|/) - [L]?

(Source)

GmonC
Didn't work either. Which is odd, because this *should* work already. I'm starting to hate Wordpress, might as well try to configure a subdomain to access this folder and get rid of the problem.
Joel Alejandro
Although it didn't work, I'm gonna take this one as as accepted answer, as it is the most complete one.
Joel Alejandro
I would try Wordpress official forums. I've had some strange problems in the past in this CMS and they solved. If it's not working, try to insert some garbage in your .htaccess and see if it's really working, maybe it's another problem with your installation. Good luck!
GmonC