I believe you need something like 30 or 50 posts to create a new thread. We had a lot of spammers in the past who would create an account and start posting a bunch of spam in new threads, which resulted in the post count requirement.
There should be a thread already created that fits closely enough with whatever you want to say that you can post your thoughts in for now, though.
"Anthony Carter...I still can't get over it." ~ Mike Rice