title: Error while building OpenCV examples on ubuntu
body: <p>I've used this tutorial to build OpenCV on ubuntu.
  Everything goes well until I try to build the examples. when I do this:</p>
  <blockquote>
  <p>sh build_all.sh</p>
  </blockquote>
  <p>many of the same error occurs:</p>
  <blockquote>
  <p>compiling tree_engine.cpp</p>
  <p>/usr/bin/ld:
  warning: libavutil.so.49, needed by
  /usr/local/lib/libopencv_highgui.so,
  not found (try using -rpath or
  -rpath-link)</p>
  </blockquote>
  <p>for each example the same error occurs.
  The code compiles but trying to run the compiled code will fail with error:</p>
  <blockquote>
  <p>./tree_engine: error while loading
  shared libraries: libavutil.so.49:
  cannot open shared object file: No
  such file or directory</p>
  </blockquote>
  <p>I have no idea what this libavutil is.</p>
  <p>I use ubuntu 10.10</p>