Problem configuring Apache/Wordpress on subdomain

Question

I have two servers (one LAMP, one Windows) and one website with an associated blog. I'm running the main site on the Windows server, and the blog on the LAMP server, using Wordpress. The main site is accessed at http://folketsting.dk (it's in Danish -- sorry), the blog is accessed at http://blog.folketsting.dk (this link is bad, read on).

The main site works fine. The blog works, except for the frontpage. Example of working post: http://blog.folketsting.dk/2009/10/09/ftlive/. The frontpage of the blog (http://blog.folketsting.dk) shows html from http://folketsting.dk however (except for the css and javascript). In fact, any other URL than the frontpage "works", and gets served by Wordpress e.g. http://blog.folketsting.dk/foo.

I cannot -- for the life of me -- understand how the LAMP server running http://blog.folketsting.dk manages to serve up content generated by the Windows server running http://folketsting.dk. Looking at the response headers at http://blog.folketsting.dk, it's evident that the content originates from Apache, not IIS.

I'm pretty sure it's not a DNS-issue, since the problem is evident even when accessing the raw IP, eg. http://130.226.142.141/ vs. http://130.226.142.141/foo. I'm thinking it's a bad config in Apache... any clues?

UPDATE: As requested, here's the apache conf file for the non-working site. Incidentally, another Wordpress blog is running on the server (though not on a subdomain), and it is not exhibiting this quirk.

<VirtualHost *:80>
    ServerAdmin webmaster@localhost
    ServerName blog.folketsting.dk
    ServerAlias blog.folketsting.dk

    DocumentRoot /var/www/blog.folketsting.dk
    <Directory />
            Options FollowSymLinks
            AllowOverride All
    </Directory>
    <Directory /var/www/>
            Options Indexes FollowSymLinks MultiViews
            AllowOverride All
            Order allow,deny
            allow from all
    </Directory>

    ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
    <Directory "/usr/lib/cgi-bin">
            AllowOverride None
            Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
            Order allow,deny
            Allow from all
    </Directory>

    ErrorLog /var/log/apache2/error.log

    # Possible values include: debug, info, notice, warn, error, crit,
    # alert, emerg.
    LogLevel warn

    CustomLog /var/log/apache2/access.log combined

Alias /doc/ "/usr/share/doc/"
<Directory "/usr/share/doc/">
    Options Indexes MultiViews FollowSymLinks
    AllowOverride None
    Order deny,allow
    Deny from all
    Allow from 127.0.0.0/255.0.0.0 ::1/128
</Directory>

</VirtualHost>

Answer 1

Which rewrite rules have you set up in your .htaccess file in the WordPress install directory?

It's probably a longshot but it could be a rule with a [P] flag.

Answer 2

The problem turned out to be an index.html file in the blog root directory with the html in it (I have no idea how it got there...). Thanks goes to Jakob Andersen (http://intellect.dk/) for suggestions.