The text file in that post has the wrong extension: $es.js.v1.7.txt The version number there is breaking it. Only .js.txt or .js would work, not .js.v1.7.txt.
I think that script is old anyway. Aussieboykie has posted "version 2" of it in two other threads:
(I'm not sure why there are two threads for the 2nd version. Have msg'd him to ask which to keep and which to get rid of.)