I'm new to mining and decided to mine Maxcoin to start with ...

Using MacMiner and getting lots of this:

(5s):0.000 (avg):0.000h/s | A:0  R:0  HW:0  WU:0.0/m  WUE:nan%         
(5s):0.000 (avg):0.000h/s | A:0  R:0  HW:0  WU:0.0/m  WUE:nan%         
(5s):0.000 (avg):0.000h/s | A:0  R:0  HW:0  WU:0.0/m  WUE:nan%         
(5s):0.000 (avg):0.000h/s | A:0  R:0  HW:0  WU:0.0/m  WUE:nan%         
(5s):0.000 (avg):0.000h/s | A:0  R:0  HW:0  WU:0.0/m  WUE:nan%         
(5s):0.000 (avg):0.000h/s | A:0  R:0  HW:0  WU:0.0/m  WUE:nan%         

Does anyone have any ideas why?