Log out of your account close your browser, re open it, re sign back in. There is no reason why you can't publish your post. There is no SP requirement.
Editing because I can't respond. That message should only pertain to trying to upvote, your steem power (3 when you sign up) is too small to vote on content. However it shouldn't effect your ability to author new content. I am searching for a solution for you.
Done. That's what I get: "abs_rshares > 50000000 || o.weight == 0: voting weight is too small, please accumulate more voting power or steem power"
I can not find anyone that knows why you get this message :(