Hi,
I'm having the same problem. I also noticed that ping router works, ping my fileserver works and ping 127.0.0.1 works. BUT ping localhost didnt work. It tried to ping address ::1: (yes, ::1: is correct, not a typo or misunderstading

)
Now have now set this two options differently:
1. Network and Internet > Network sharing center > Advanced sharing settings and from there "File sharing connections". It was set to "Use 128-bit plaa plaa.." and I changed it to "Enable file sharing on devices that use 40- or 56-bit encryption"
2. I went into the driver properties, clicked Advanced / Task Offload, and I turned this feature off. Just like mpowrie told us to do.
I will see if these two help. If it does, I will try to turn those settings back, one at the time to see which one was the killer move. Gonna let you guys know later today o/
After test
Well.. I did perform an operation succesfully without the ::1: bug that kills the network connection.
BUT I still have problem moving with filetransfer from fileserver. The transfer will just... calculate :<