Basic Trouble Shooting

Some reasons the arm occasionally fails to launch do to it hanging on the xtion. So try unplugging the xtion and plunging it back into different USB ports, killing the launch files and relaunching them. If these fail try launch the arm directly running roslaunch jaco_driver mico_arm.launch If this fails try going into the kinova package you downloaded from above and run the ExampleRestoreFactoryDefault the relative path to the file to compile it should be
~/kinova/Documentation/API Examples/Ubuntu/64Bits/Examples/ExampleRestoreFactoryDefault/Debug Compile the executable if it has not been done already and run it and the try to rerun the arm Overall the arm is very finicky so try these things a few times.

If colliding with anything just put your hand in front of it to prevent it form moving. If the arm falls catch it and try to place it in a balanced position. Turn off the robot and charge it, and try to home the arm again.