I have an [IkiWiki site](http://ocikbapps.uzh.ch/gc3wiki), which works
fine, except for one page which I cannot edit with the CGI.  Only this
single page is failing, editing every other works as expected.

When clicking every button (well, except "Cancel") on the edit form, I
get a "302 Found" page in the browser; the Apache logs show:

    [client XXX] malformed header from script. Bad header=according%20to%20the%20availab: ikiwiki.cgi

Capturing the output from `ikiwiki.cgi`, I see that just these two
lines are sent:

    Status: 302 Found
    Location: https://ocikbapps.uzh.ch/gc3wiki/ikiwiki.auth.cgi?_submitted=1;do=edit;..;_submit=Preview;attachment=

The total size in bytes of the reply is 16189; I thought this might be
an issue with Apache imposing some limit on the header size; indeed,
`tcpflow` shows that the "302 Found" message is encapsulated into an
HTTP 500 "internal server error" response.

So I added this to Apache's config (std Debian 6.0):

    # cat /etc/apache2/conf.d/limits.conf
    LimitRequestFieldSize 65534
    LimitRequestLine 65534

But I'm still getting the same error.

Any suggestions?