To use these tests you will need to include webdriver in your java classpath. You can either build these from source, available here http://code.google.com/p/selenium/source/checkout; or download prebuilt libraries from http://code.google.com/p/selenium/downloads/list

Native events need to be enabled in order to use the keyboard handlers. At the time of writing, November 2009, webdriver includes both native and simulated versions of the internet explorer and firefox drivers. Here's a search query for the webdriver package for native events in firefox http://www.google.com/codesearch?hl=en&lr=&q=native+event+firefox+package:http://selenium\.googlecode\.com&sbtn=Search
Native events can be enabled by creating a custom firefox profile.