Most likely, the problem is that you typed the install location as:

"usr/local/bin/emphatic"

That's wrong because it doesn't have a leading slash. The install script works fine in creating the directories and putting the files there (since the FTP session starts out in the root directory) but when it tries to SITE EXEC the file it's trying to launch "usr/local/bin/emphatic" from within the /usr/local/bin/emphatic directory, meaning it's actually trying to launch "/usr/local/bin/emphatic/usr/local/bin/emphatic".

Re-run the install with the leading slash in the install path and it *should* work.