While I don't know the specifics, and I know that some other people might....If I am not mistaken, even though USB is a standard I don't believe that there is any standard for the amount of power they can put out and thus it is possible that one laptop which can send more power through can work with longer cables. Once you start attaching multiple cables via connectors or whatever, I know this sucks more power and it might not be possible for some laptops to give it enough power to work. While again, I don't know if this would work, maybe if you tried a powered USB hub in between cables it MIGHT help...Just an idea...