Hi,

IMHO there is a bug in the configuration tutorial on 
http://www.ros.org/wiki/ROS/Tutorials/InstallingandConfiguringROSEnvironment 
in section 3.2:

If you run the first line of the listing, the $ROS_PACKAGE_PATH variable 
is expanded, which should not be done like that. If there is no 
$ROS_PACKAGE_PATH set on call time of the command, the string is 
expanded to "export ROS_PACKAGE_PATH=~/ros_workspace:"

If you want to rosmake your first package this results in
[rospack] Error: package/stack shutter depends on non-existent package 
roscpp

Greets,
David