Ohai,
to fight the spam waves we’ve seen in the recent weeks, we’ve modified the permissions here in the community forums to forbid new topics (threads) to be created by newly signed up users (trust level 0).
Basic users (trust level 1) can create new topics and you’ll be automatically promoted to that level after a bit of reading in the forum (reading 3 topics with a total of 15 posts in 10 minutes should suffice).
Sorry for the inconvenience
Evgeni, for the infra team