Make sure you have Chrome installed (the version directly from Google).
Download the latest version of the Chrome Driver here. It is just a single executable file (e.g., chromedriver.exe). Let's say you have put it into the c:\browser-drivers folder.
Before running the test case, set a system property to tell Wicket Page Test to use the Chrome Driver and the full path to the driver. For example, in Eclipse in the Run Configuration, set the properties with VM arguments:
-Dcom.ttdev.wicketpagetest.webdriver.class=org.openqa.selenium.chrome.ChromeDriver -Dwebdriver.chrome.driver=c:\browser-drivers\chromedriver.exe
With Maven, run it like:
mvn -Dcom.ttdev.wicketpagetest.webdriver.class=org.openqa.selenium.chrome.ChromeDriver \ -Dwebdriver.chrome.driver=c:\browser-drivers\chromedriver.exe \ install
It is unfortunate that the Firefox driver in Selenium (v2.31.0) doesn't work with the Firefox 20 or later (at the time of this writing, it is at 29). So, you must use an older version.
To do that, download Firefox 19. Unpack it into, say, c:\firefox-19. Set the properties like:
-Dcom.ttdev.wicketpagetest.webdriver.class=org.openqa.selenium.firefox.FirefoxDriver -Dwebdriver.firefox.bin=c:\firefox-19\firefox.exe
With Maven, run it like:
mvn -Dcom.ttdev.wicketpagetest.webdriver.class=org.openqa.selenium.firefox.FirefoxDriver \ -Dwebdriver.firefox.bin=c:\firefox-19\firefox.exe \ install