If you're using the Enterprise Edition of screen-scraper, this can be done via the web interface.

In the Professional or Enterprise Editions of screen-scraper, create a text file in screen-scraper's folder named register.txt file that contains a single line with the email address under which you registered screen-scraper. Start up either the screen-scraper server or invoke screen-scraper from the command line. screen-scraper will read in that file, validate the license, then write the result of the validation to a file called register_result.txt. Once the license has been validated, the register_result.txt file can be deleted.