From your last screenshot, it looks like you’ve moved the entire pixlet source folder into /usr/local/bin. What we wanted to do was move the built binary there instead.
Move the source back to your home directory
> sudo mv /usr/local/bin/pixlet /home/pi/pixlet
> cd /home/pi/pixlet > sudo PATH=$PATH:/usr/local/go/bin GOPATH=$HOME/golang make build > sudo mv pixlet /usr/local/bin/pixlet