Couple of things I'd check are:
Making sure you include the httpd-vhosts.conf
# Virtual hosts
Include /Applications/XAMPP/etc/extra/httpd-vhosts.conf
Set up hosts:
navigate to Macintosh HD/private/etc/hosts, in a text editor and click Open. Then add this line:
127.0.0.1 wrks.tk
And maybe try:
<VirtualHost *:80>
DocumentRoot "/Applications/XAMPP/xamppfiles/htdocs/DNS"
ServerName wrks.tk
ErrorLog "/logs/wrks.tk-error_log"
CustomLog "/logs/wrks.tk-access_log" common
</VirtualHost>
You may also want to set up localhost again.
<VirtualHost *:80>
DocumentRoot "/Applications/XAMPP/xamppfiles/htdocs"
ServerName localhost
</VirtualHost>
Sorry if some of these paths aren't accurate, you will need to check them against your xamp folder structure.
The simplest implementation I found is this: http://iwearshorts.com/blog/adding-a-virtual-host-vhost-in-xampp-on-a-mac/