I assume both tablets have static IPs on the same network, e.g. 192.168.5.5 and 192.168.5.6 or something similar? Do a "netstat -r" in an xterm to see how it is trying to route things. You might need to do "route add default gw <usb n810 wifi IP>" on the remote tablet and "route add default gw <pc usb IP>" on the usb connected one. Also try pinging between to see if you have a connecton (you might need rootsh).