thats strange, i have one copy and i play on two computers. both online. either the anti-piracy is really weak or you cant be logged in both places at the same time.
Try playing online with both machines at the same time and see what happens.
I was given a second CD Key to use online from EA when I complained about not being able to log in with my first account that I used for the limited edition content. So basically for $30 (which is what I paid originally for the game) I got 2 CD Keys to play online with. They also gave me 2 $20 off Coupon Codes (I called twice, 8 days apart to see if they fixed the issue) and I got a code each time. Used them on my BF3 pre-orders.
