Hi Damian,
Just want to provide more information for your debugging. I have downloaded the latest XAMPP version and latest CJT. The same error still exist during installation of CJT.
XAMPP: v3.2.1
Download link: http://sourceforge.net/projects/xampp/files/XAMPP%20Windows/1.8.3/xampp-win32-1.8.3-4-VC11.7z/download
WordPress: v3.9
Download link: https://wordpress.org/download/
CJT: v7.0.1
Windows OS: Windows 7
Hope you can help me to resolve this issue soon as local development on my desktop is very important to me.
Thanks
Justin