[ros-users] Installation problem in ROS

Hi all
I have installed the the ROS Software from the instructions given here :
http://www.ros.org/wiki/ROS/Installation/Ubuntu

but the subsequent tutorials are not installing as:

rosinstall python-script tries to access
uri: https://code.ros.org/svn/ros/stacks/ros_tutorials/branches/boxturtle

with the error:
>
ahhhhh got an error from the interwebs: <urlopen error [Errno -2] Name
or service not known>
couldn't load config uri
http://www.ros.org/rosinstalls/ros_boxturtle_tutorial.rosinstall

Could some help me with the same.

Regards
Anish Nahar