Wiki

Hello,

I have set up a Wiki and in the process of creating a few pages to give it a basic structure, I came upon this odd (and quite unwanted) behaviour:

Whenever I submit a change to a page, I get an error message:
With Safari, it reads
This page cant be found.
Safari cant open the page http://www.afsabadell.org/moodle/mod/wiki/view.php?id=55&page=edit/SuperTex because the page doesnt exist. Make sure the address for the page is correct.

With Firefox, the wording is somewhat different
Found
The document has moved here.
Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

Now the odd thing is that the changes *are* saved, but I can't reasonably expect my online students to understand or cope with that.

Any ideas of what I could try to fix this?
I'm the admin and did set up the Moodle.
Something which may (or may not) be related is that I wasn't allowed to copy .htaccess files when installing the Moodle (and if that's not a source of problems here, it may be elsewhere ><;; DOH!)