I have no experience with the 3DS, but I have seen computers where WiFi connected, but didn't get an IP address. Is it possible to see if it has an IP address? According to the first message, the DHCP process worked up to the point where an address is sent to the 3DS. Since there doesn't appear to be a DHCPDECLINE, I can only assume it accepted an address. If it got that far, yet still doesn't have an address, then there's likely some problem with the 3DS.