U46MK2 and Cross LE Help

Macbook Pro 15 inch
MAC OSX 10.6
I am trying use an external mixer with the U46MK2 and Cross LE but when I configure Cross to use external mixer I only hear sound coming out of outputs 1 and 2 not 3 and 4. Do I need to use a power supply adapter since whenever I connect the U46MK2 to my macbook pro it complains about the device draining too much power. Do I need to upgrade to Cross ? ?
should I use windows instead ?
Thanks for you help.
MAC OSX 10.6
I am trying use an external mixer with the U46MK2 and Cross LE but when I configure Cross to use external mixer I only hear sound coming out of outputs 1 and 2 not 3 and 4. Do I need to use a power supply adapter since whenever I connect the U46MK2 to my macbook pro it complains about the device draining too much power. Do I need to upgrade to Cross ? ?
should I use windows instead ?
Thanks for you help.