I just uninstalled the Office 2010 Technical Preview from my laptop and installed the Beta version.
After the installation it needed a product key change in order to activate Office, no problem i thought.

However when trying to change the product key i received the error "The setup controller has encountered a problem during install." 

A quick search reveiled that the solution is to run "C:\Program Files\Common Files\microsoft shared\OFFICE14\Office Setup Controller\setup.exe" as an administrator.