Sorry for the delay in reply, I wanted to test out your problem. I tried with a fresh Raspbian image and I didn't face any problems.
It looks like the folder name in your computer is
Arduberry and not
ArduBerry. So that seems to be causing the trouble. At step 3 here we have mentioned as
Arduberry, thanks we will get it changed to
/home/pi/Desktop and run
sudo mv Arduberry ArduBerry
and then follow the steps 4 and 5 from here.
Please let us know if this helps,