SFTP into Google Compute Engine from windows 7 Client

Question

I am trying to SFTP a Debian-7-Wheezy-V20140807 Instance on Google Compute Engine from Windows 7, 64 Bit Client.

Finally my problem got solved using this

Also in Windows I first installed Cygwin and then used set the Environment Variable CLOUDSDK_PYTHON to python instead of C:\python27\python.exe

and finally from cygwin ran this

curl https://sdk.cloud.google.com | bash

All the instructions below are symptoms. First i tried Filezilla, which errors out with message

Status:   Waiting to retry...
Status:   Connecting to 23.xx.xx.xx..
Response: fzSftp started
Command:  open "Abdul@23.236.51.19" 22
Error:    Disconnected: No supported authentication methods available (server sent: publickey)
Error:    Could not connect to server

User     :root

password : 
<same as passphrase set up on running SSH key>

I have also tried gcloud compute copy-files

gcloud compute copy-files deccan4-clone:/etc/ssh/ssh_host_rsa_key.pub  ssh_host_rsa_key.pub --zone=us-central1-b

ssh_host_rsa_key.pub: **Permission denied
ERROR**: (gcloud.compute.copy-files) exit code 1: /usr/bin/scp -i /home/Abdul/.ssh/google_compute_engine

sudo gcloud compute copy-files deccan4-clone:/etc/ssh/ssh_host_rsa_key.pub  ssh_host_rsa_key.pub --zone=us-central1-b

WARNING: You do not have an SSH key for Google Compute Engine.
WARNING: ssh-keygen will be executed to generate a key.
This tool needs to create the directory /root/.ssh before being able
to generate SSH keys.

Do you want to continue (Y/n)?  Y

Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/google_compute_engine.
Your public key has been saved in /root/.ssh/google_compute_engine.pub.
The key fingerprint is:
 root@deccan4-clone

**ERROR: (gcloud.compute.copy-files) some requests did not succeed:
 - Insufficient Permission**

I have also tried

Abdul@deccan4-clone:/home/a_rahman_synergywell_com$ gcloud compute copy-files de                                                                                                            ccan4-clone:test.txt  test.txt --zone=us-central1-b

scp: test.txt: No such file or directory
ERROR: (gcloud.compute.copy-files) exit code 1: /usr/bin/scp -i /home/Abdul/.ssh                                                      
/google_compute_engine -r Abdul@23.236.51.19:test.txt test.txt

Please let me know if I am missing some key setup.