nPack source code is available for purchase for 30$ under the following terms:

You may not sell or distribute:
     - The source code or any part of it. 
     - A modified part of the source code. 
     - A compiled version of the source code. 
     - A modified compiled version of the source code.

You may sell an application which uses the compiled source code or a modification of it.

Please e-mail neox@petools.org.ru in order to recieve instructions on how to purchase the source code.

OR

http://shareit.com/product.html?productid=300161907