Hello,
Thanks for creating this script. It saved me a ton of time setting up NUT server.

I did run into one issue where apache was not installed with the script, this was verified because the command a2enmod cgi was not found.

To fix, here is what I did:

upsd -c stop

sudo apt-get update
sudo apt-get install apache2

sudo ./nutinstall.sh

I hope this helps anyone who comes across it, or the fix can be added directly into the script.