enigma1 - 1:42 pm on Jan 10, 2012 (gmt 0)
The strange URL contains only folder names really existing on my server
Looks like you are having problems with your website code and you should fix it. If these were physical static pages you wouldn't care about it and googlebot wouldn't even see the mangled links. Since you see them listed it implies your code is prone to url poisoning.
Somehow these links once accessed are replicated inside your various pages and anyone could theoretically create an infinite number of duplicated pages for your domain.
It's not a problem with apache and the htaccess rules can't fix this problem, you're just hiding the culprit in the particular case.