What's causing the problem:
This is a pretty rare problem, but can be caused by an encryption key used by Lumo Play becoming corrupted. The last step of activating your license is an encrypted handshake between your new Lumo Play installation and the server. If the encryption key gets corrupted due to a disk failure, unexpected power outage, or other reason, this handshake can fail and cause the program lock up.
Exit Lumo Play and open Windows Explorer. In Windows Explorer's address bar type %APPDATA% and press enter. Locate the folder called Microsoft and open it. Inside the Microsoft folder, look for a folder called Crypto. Delete the Crypto folder, and then re-launch Lumo Play. You should be able to activate your installation properly now.