The drivers/ctree.drivers folder contains DLL's, LIB's, .h files, etc. that are required by your applications. You will need these files when you experiment with the tutorials. Each tutorial has a section explaining any requirements for these files. The files in this folder are the shared components needed by each programming language to run, link, or compile tutorial code.
Resources:
c-tree Database API for Other Languages
FairCom allows you to use NAV APIs with the language of your choice: