Nintendo 3DS save backup

Hey guys,
My son has a new 3ds xl and has put in over 300 hours on monster hunter generations. He wants to back up his info to the laptop wirelessly (taking out the sd card requires removing the battery cover) We followed all the instructions from the Nintendo website but I cannot get it to work. I can see the 3ds show up in the network tab of my computer, but when I click it I get Windows cannot access \\3ds check spelling and such with an error code 0x80070035 I can't seem to find anything on the net that helps so I hope you guys can. Running win7 with an ASUS RT-N66U router

Thank you