technically you aren't suppose to.. but you can.
just try and make sure everything is unique as far as gmail, ip, domain if you can.. and run ccleaner to delete cookies, flash cookies, cache and all that good stuff just to be extra safe.
i'm not 100% sure about domain.. but when i used a second voucher i made sure to use a different domain then i had before just in case.. i also deleted my campaign info from the first one. i used the same keywords and had no problem.
I'm really curious about using the same domain.. if it's just a safety precaution to use a different one.. or if someone really has had their account disabled or whatever.