That link doesn't show the readme file for the package.

What you need to do is read the "Readme" file that came with the Dylan package. It should tell you how to go about decoding the file. 

Is it for Millennium Baby 3? 

Basically what you do is open RTEncoder.

Locate the coded file (Dylan one)

Locate the .obj file for the figure that the package works with IE: Millennium Baby 3

Then decode by pressing the button.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi