You don't have to replace anything, it's literally in that location. But for the YouTube clone script to actually work, you need several other programs, which unfortunately requires compiling your own version of ffmpeg.
And yes, I mean it's not a good idea to run such a script on your DreamHost account. I'm almost positive you'll experience tons of issues (mostly with ProcWatch killing ffmpeg) which may possibly lead to DH Staff asking you to disable the script entirely.
Of course, I can't say that with certainty and you're more than welcome to try, but I personally won't help you any further. Nor can I honestly, as I've tried getting the script to work before myself to no avail, as someone before said it was "broken" and and the author claimed it wasn't.
I will tell you however, that installing the programs needed requires some decent knowledge of working in a *nix shell prompt, as the installation of a couple of those programs isn't exactly easy I'm afraid. But if you get it working somehow, I would be very interested to hear about your experience!