I installed d2 onto my macbook pro laptop recently. However, when I use my f keys (f1, f2 etc) on D2, my skills don't work, only the computer things. (f3 opens all my windows, f4 opens dashboard)

is there a way to disable that temporarily?

Use the checkbox in the "Keyboard" tab of "Keyboard" system preference.

The "fn" key in the corner of your keyboard can be used to reach the keys. Also under sytem preferences go to Keyboard & Mouse. By default the function keys do Mac OS related things. You can reverse the behavior by checking the box next to "Use the F1-F12 keys to control solftware features."