I've been mining for a day, and doing about 2.75%-3.5% of the work, and my payouts all show up as 0.00000000BTC.
EDIT - Also my hashrate shows up as .3 MH/s when my miner is showing a solid .6 MH/s.
Hash rates are calculated and are just estimates. Your earnings should be calculating..
Only payouts which haven't been traded will show up as .000000 so observe the status first.