trouble creating launch file

edit

hello Guys , I am trying to create a launch file which would execute the command:

rosrun ardrone_brown ardrone_driver

so here is the launch file: <launch> <node name="ardrone_driver" pkg="ardrone_brown" type="ardrone_driver"/> </launch>

roslaunch ardrone_brown ardronematlab.launch

and here is the corresponding output when I execute the launch file::

... logging to /home/karthik/.ros/log/88e084e4-84d4-11e1-a4e9-f04da263aca7/roslaunch-karthik-laptop-6444.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://karthik-laptop:47029/
SUMMARY
========
PARAMETERS
 * /rosversion
 * /rosdistro
NODES
  /
    ardrone_driver (ardrone_brown/ardrone_driver)
ROS_MASTER_URI=http://localhost:11311
core service [/rosout] found
process[ardrone_driver-1]: started with pid [6462]
[ardrone_driver-1] process has died [pid 6462, exit code 255].
log files: /home/karthik/.ros/log/88e084e4-84d4-11e1-a4e9-f04da263aca7/ardrone_driver-1*.log
all processes on machine have died, roslaunch will exit
shutting down processing monitor...
... shutting down processing monitor complete
done

please give your prespective on this