Hi Krit,
The install command in their readme seems to assume you are running either as root (or on Mac OS X with write permissions to the /usr/local/bin directory). This step fails because by default you do not have enough permissions to write in this directory: ./hebe link hebe /usr/local/bin
If you go to the hebe directory and run the command as sudo, the link should be created:
cd ~/hebe
sudo ./hebe link hebe /usr/local/bin
Let me know if that solves your problem.
Cheers,
Steven