Docker error on Windows

Error message:
no connection could be made because the target machine actively refused it

Full message:
C:>docker run -p 8888:8888 -it --rm b.gcr.io/tensorflow-udacity/assignments:0.4.0
docker: An error occurred trying to connect: Post http://127.0.0.1:2375/v1.22/containers/create: dial tcp 127.0.0.1:2375: connectex: No connection could be made because the target machine actively ref
used it..
See 'docker run --help'.

- My computer env
OS : Windows 8.1 embedded
Docker Client:
 Version:      1.10.3
 API version:  1.22
 Go version:   go1.5.3
 Git commit:   20f81dd
 Built:        Thu Mar 10 21:49:11 2016
 OS/Arch:      windows/amd64

- Try it 1
http://stackoverflow.com/questions/32047660/docker-for-windows-not-working

I do it this.
1)"C:\Program Files\Docker Toolbox\docker-machine" ls 
2) Install a nightly build of Virtual Box
3) docker-machine regenerate-certs default 
(before installing a nightly build Virtual Box this commands never ended) 
4)"C:\Program Files\Docker Toolbox\docker-machine" env default --shell=cmd
5) Open Docker Terminal and set the variables 6) Close Docker Terminanl an re-open it,

Not working for me

This error occurred in CMD console...
Please do command in Docker console.