This license key will allow 5 concurrent builds, if you want to do testing with more than 6 concurrent builds let us know and we'll issue you a private beta license key.
http://downloads.finalbuilder.com/downloads/continua/beta/CT100-0001-000025.license
Edit : The license file has been updated to expired on 03/05/2013 - if you already had it installed then download it again, on the license page, delete the expired key and then add the newly downloaded one.