Accessing WP-ADMIN on Sub-Server under root domain when root already has Wordpress installed.

In my root domain, I have installed Wordpress. www.example.com

I created subserver.example.com and installed Wordpress using the install script.

Both www.example.com and subserver.example.com show their respective front pages from their own WP resources, but if I attempt to go to :

subserver.example.com/wp-admin/ I am redirected to the login page for www.example.com.

I imagine this has something to do with .htaccess rewrite rules, but rewrite rules look like someone smashed a keyboard with their fists and pressed enter...so I don't know what all of the language means.

I also don't know which root folder gets which .htaccess file.

www.example.com looks like this:

RewriteEngine On
RewriteBase /
RewriteRule ^index.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

subserver.example.com didn't create one and I can't login to access the permalink settings anyway.

How does one go about installing wordpress in a subserver without needing to worry about this?