Permalinks 400 Error – unable to update

Hello,

I have one problem when I try to “Save Changes” in wp-admin/options-permalink.php, when I choose everything else than the default option (common setting).

Let’s say that I put in the field “Custom Structure“: /%postname%/
I get the 400 Error: Bad Request Your browser sent a request that this server could not understand.

If I try to put in the same field “Custom Structure“: /postname/ or everything else that does not contain “%“, I don’t get the error, but of course, the permalinks doesn’t work.

I use Apache/2.2.0 (Fedora) Server.