@jknutter : in the subfolder Libraries , i have not found any subfolders called Libraries nested off each other. SO WHAT IS THE SOLUTION !!!
per http://www.ultratechnet.com/2013/01/arduino-problem-invalid-window-handle.html"SOLUTION: All you have to do is rename/delete(whatever you prefer) the "java" folder in the Arduino package and copy-paste the java runtime environment located in the program files folder. This is pretty simple hack which came to my mind while just trying to fix the problem. I hope this "technique" works with you.Active Bluetooth device also seemed to be a probable cause for the problem, also responsible for slow behavior of the arduino IDE. Turn off the bluetooth device of your laptop, i.e disable the network and try again launching the application."Worked for me.