Those directions I gave you were my own saved directions that I use for my setup. Nothing sketchy going on, that's just a link to what is probably CyberPower's CDN for downloads. I was trying to save you time by not finding it yourself but since you have found it just look at the download link for the power panel business edition. You should see it's the same as I gave you unless their CDN adjusts for geographical changes.
In fact I run my own web hosting company and constantly fight against people trying to hack and attack my customers. I wouldn't give anybody instruction unless I knew they were safe and tested myself.
If you login to SHH it should take you to your root folder. That's where the file should've been downloaded to originally unless you changed directories first. Just run a "ls" command and you should see the ppbe320-linux-x86_64.sh file. If not then chances are you never downloaded it and that's probably why the installation failed. Or you might have needed a 32 bit instead of the 64bit I gave you but it looks like you resolved the plugin issues anyways.