Acording to this Gamasutra report, WiiWare developers don’t get paid unless they hit a certain sales threshold.
From the piece:
Multiple sources have indicated to Gamasutra that there is a minimum amount of sales, on a per-territory basis, that WiiWare developers must reach in order to recoup any money at all for their games.
It is believed that this sales number is set in the mid-four figure range for North America, and lower four figures for individual European territories. Until a WiiWare title sells over that number, nothing will be paid out.
Full thing through there.