Problems with permanent redirects

[kgun]

1. Permanent redirects.

I made a permanent redirect from the panel on the webserver for my two Norwegian sites.

E.g.
http://multifinansit.no/ ---> http://www.multifinansit.no/

It functioned for some minutes, but then I got the following error:

"Forbidden
You don't have permission to access / on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request".

When I deleted the redirects, everything was OK again.

2. A security question:
How secure are password protected folders? They block human beings, but what about advanced site crawlers?

3. Qurious experience:
Last question: Had a qurious experience. When I was logged into the panel of my hoster for MulitiFinanceIT.com, suddenly this http://www.megaspider.com/ site popped up. Any comment?

Hope for constructive comments.