Hi Lara,
I'll put here the answer which I already sent to you via Ticket. May by it helps to someone else as well:
in your activation request is missing Unique Machine ID. There is couple things which may cause the issue. Sometimes virtual machines aren't able get such ID. Other possibility is some security settings on your OS which deny D32DS installer from getting such number.
In some cases helps backup and delete content of the c:\ProgramData\FLEXnet\ folder and try activation again. The folder is hidden by default.
More info you can find in help.txt file which is part of one of the archives.