Re: Bitstars.net Signature Campaign – up to 0.1 BTC and more per month for 50 posts
when payment will be made 
Read the op. 30 days after you signed up, but allow up to 48hrs for payment.
It has been a while since OP has posted though, it would be nice to get a word from him to make sure he has not ran away.
Would it matter even if he did? Monbux is issuing the payments apparently:
Payments will be made using a escrow service provided by user monbux. His escrow thread: https://bitcointalk.org/index.php?topic=631008.0