No reply to my request from the Guest Services Representative in 30 hours time...
Time for a User's workaround:
I play from a Windows user account with limited rights, and most programs know how to activate the admin for updates. Not this one.
I tried to start WGT from the admin account, to no avail. Not even a splash screen :(
Only when I started it from my user "as an admin", the updates would start, granting me access to the game. Only downside, I had to login again.