I have already done these steps in erle@erle-brain-3.
Then I go in blockly_ws -> source devel/setup.bash
blockly_src -> roslaunch robot_blockly robot_blockly.launch
... logging to /home/erle/.ros/log/73c397a8-0b1c-11e7-a8bf-b827ebedd028/roslaunch-erle-brain-3-2332.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.
started roslaunch server http://erle-brain-3:37489/
* /rosdistro: kinetic
* /rosversion: 1.12.4
core service [/rosout] found
process[robot_blockly_backend-1]: started with pid 
process[robot_blockly_webserver-2]: started with pid 
Traceback (most recent call last):
File "/home/erle/blockly_ws/src/robot_blockly/scripts/pywebserver.py", line 22, in
httpd = socketserver.TCPServer(address, Handler)
File "/usr/lib/python3.4/socketserver.py", line 429, in init
File "/usr/lib/python3.4/socketserver.py", line 440, in server_bind
PermissionError: [Errno 13] Permission denied
[robot_blockly_webserver-2] process has died [pid 2351, exit code 1, cmd /home/erle/blockly_ws/src/robot_blockly/scripts/pywebserver.py _name:=robotblockly_webserver _log:=/home/erle/.ros/log/73c397a8-0b1c-11e7-a8bf-b827ebedd028/robotblockly_webserver-2.log].
log file: /home/erle/.ros/log/73c397a8-0b1c-11e7-a8bf-b827ebedd028/robot_blockly_webserver-2*.log
Then in a browser, I obtain
I another post, they had to get ride of the port number to make it work. That's what I did and I got the following result: