Hi, all: After manually install *ros Layer 1: Install core libraries *from source (refer to http://www.ros.org/wiki/fuerte/Installation/Ubuntu/Source ) LD_LIBRARY_PATH now changes to /opt/ros/fuerte/lib, and nothing else. However, LD_LIBRARY_PATH is set as LD_LIBRARY_PATH="/usr/lib:/usr/local/lib:/usr/lib/llvm-3.0/lib:${JMF_HOME}/lib:$LD_LIBRARY_PATH" in /etc/environment This is really weird, because even after rebooting, LD_LIBRARY_PATH is now nothing... It seems somewhere else but not /etc/environment rewrites LD_LIBRARY_PATH after it has been set to the above values as in /etc/environment . Can anybody please help ? Urgent... Best Regards Pei -- Pei JIA Email: jp4work@gmail.com cell: +1 604-362-5816 Welcome to Vision Open http://www.visionopen.com