You can't set shutter speed in all modes. Try Tv, then press the Q located above the wheel. The shutter setting is upper left next to "Tv". Use the wheel behind the shutter button to increase or deacrease.
I have the same problem with a 6D. Tried EOS 3 and it still will not work with a network drive. Tried this on 3 different PC's and none worked with anything other than C or a USB drive.
