Custom Structure permalinks error 404

Question

Mehdi, it’s common problem, as Apache server is not set by this way by default. Your problem can be solved with some very simple steps (simply quoting Samuel B):

If you want to use permalinks, you will need to make a change inside another file:
apache > Conf and find the file httpd.conf. Open that in a text editor. Use the search facility in the editor to find “rewrite”. The line you need looks like this:

#LoadModule rewrite_module modules/mod_rewrite.so

You need to take away the hash sign so it looks like this

LoadModule rewrite_module modules/mod_rewrite.so

Now just save the file.

Reference: WordPress Support – Answer by Samuel B

And a warning:

REMEMBER:
NEVER EVER EDIT A CORE WORDPRESS FILE, IT’LL SIMPLY MAKE YOUR WP BUGGY.