This is a really weird problem that I have been having. When I download Scriptaculous from the official web site, script.aculo.us, bundled in the ZIP is prototype.js version 1.6.0.1. This works perfectly fine, I can follow along the wiki examples and begin learning. However, when I upgrade to prototype 1.6.0.2 (the latest version) from prototypejs.org everything breaks. I have read the documentation, named the new file prototype.js and nothing works. Any help is greatly appreciated!
scriptaculous is a JS library built on top of prototype. As such, they will be behind prototype in their release schedule. To ensure that scriptaculous works only use it with the prototype file that came in the download.
Sure, given enough time and energy, you can find all the changed references from prototype 1.6.0.1 to 1.6.0.2 but is there really something in the newer version of prototype that you need today? If not, then just wait for the scripaculous to update.