Hello,

I just thought I should share my solution for this error. I found it by a coinsidence, and I'm not sure if it works on ordinary domains as well. This also implies that I am no guru on this, so if this don't work for you, I will not be able to help you further on this topic. Sorry!

In your .htaccess, add this line:
RewriteBase /

This makes your new .htaccess look like this:

Options +FollowSymLinks
RewriteEngine On
RewriteBase /

AddEncoding gzip .gz
AddEncoding gzip .gzip
<FilesMatch "\.(js.gz|js.gzip)$">
  ForceType text/javascript
</FilesMatch>
<FilesMatch "\.(css.gz|css.gzip)$">
  ForceType text/css
</FilesMatch>

RewriteCond %{REQUEST_URI} .*/http-bind
RewriteRule (.*) /http-bind [L]

RewriteCond %{REQUEST_URI} !^/index\.php
RewriteCond %{REQUEST_URI} !/ow_updates/index\.php
RewriteCond %{REQUEST_URI} !/ow_updates/
RewriteCond %{REQUEST_URI} !/ow_cron/run\.php
RewriteCond %{REQUEST_URI} (/|\.php|\.html|\.htm|\.feed|robots\.txt|\.raw|/[^.]*)$  [NC]
RewriteRule (.*) index.php

Good luck! :)