To launch the game, run thehobbit/Hobbit.com.
The .zip contains only two files: hobbit.com and hobbit.dat. The executable file is hobbit.com. If you're having problems, try mounting The Hobbit using D-Fend.
DOS Games made for DOS require an emulator to run on Windows. Use DOSBox or a frontend like D-Fend Reloaded and read this guide to play DOS games on your Windows PC.