My program is just a GUI for the base program, NUSGrabber.exe. If you would like to manually download titles via the command line, there is a helpful tutorial
if you go into "Settings/FAQs".
For simplicity's sake, I'll also show you how here. If you don't already have the base program, you can tell my program to not remove the resources it uses upon exit by selecting the appropriate option in the Settings dialog. Then, assuming you're running Windows 7 or higher, you can Shift-Right Click the folder where NEW-NUSGrabberGUI.exe is stored at and select the new option "Open with Command Prompt" or "Open in Powershell". If you've selected the Command Prompt, then type in "NUSGrabber.exe <titleid>". If you've selected Powershell, then type in "./NUSGrabber.exe <titleid>". Replace <titleid> with your title ID, then wait for it to download.
Good luck! Many titles, I've found, are no longer served via the NUS. Either that, or the program doesn't work very well anymore since Nintendo's updates.