Sorry, the chmod is my mistake.
From what it gave you after the 'ls ffmpeg' command, it means that you didn't put ffmpeg in the directory of toribash.
Try copying ffmpeg it again to Toribash directory on the desktop. Then, from the terminal:
cd Desktop/Toribash
ls ffmpeg
(should give you: ffmpeg)
Then run the command that I wrote you before.
(replace ffmpeg with ./ffmpeg there)