title: Error: Program "/NDK-build" not found in PATH
body: <p>I need help. I'm trying to install and configure <code>OpenCV 2.4.7 library</code> in my computer (Ubuntu 12.04). After run OpenCV samples appears those errors in my Console:</p>
  
  <p>Cannot run program <code>"/NDK-build"</code>: Unknown reason</p>
  
  <p>Error: Program <code>"/NDK-build"</code> not found in PATH=<code>[/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games]</code></p>
  
  <p>I've seen numerous tutorials and nothing worked. I ask you to be very specific since I am "new" programming and also because my mother tongue is not English (I have some difficulties). Thank you!</p>