u won't run into any problem if u have done the following as given in installation instructions page http://www.ros.org/wiki/ROS/Installation/Ubuntu/SVN

"You'll need to configure your environment to enable the tutorials, just like you did with the ROS installation. The command below will automatically load the environment variables in your bash shell:

echo "source ~/ros-tutorials/setup.sh" >> ~/.bashrc
. ~/.bashrc

If you just want to change the environment of your current shell, you can type:

source ~/ros-tutorials/setup.sh"


if u still have problem then just check that the last line of .bashrc
file has "source ~/ros-tutorials/setup.sh"

and just make sure that ~/ros-tutorials/setup.sh file has the following
"export ROS_PACKAGE_PATH=/home/yourhomefolder/ros-tutorials/ros_tutorials:/home/yourhomefolder/ros-tutorials/ros_pkg_tutorials"

where yourhomefolder is your login name.