So this kinda happened to me to but if you already found the solution, then this is from those who don't feel like watching the video i guess. This is what worked for me tho. When you first download Plutonium, you just get the .exe file - it creates the folders and downloads everything else when you run it for the first time.
Here's what to do:
Create a folder for it first:
Make a new folder somewhere (like C:\Games\Plutonium or on your Desktop)
Move the plutonium.exe file INTO that folder
This is important - it needs its own folder to download all the game files into
Run it:
Double-click plutonium.exe from inside that folder
It will start downloading all the necessary files
This includes the COD game files, which can be several GB
If you get that download error again:
Just try running it again - sometimes the servers are busy
Or try the PowerShell command from that folder (Shift + right-click the folder, open PowerShell, then .\plutonium.exe -timeout 0)