I'm wondering if this problem also occurs with other libraries or just the Arduino library?  I'm only somewhat familiar with Ubuntu, so great to know it does all "work" eventually in that environment (no reason it shouldn't really).

If you're interested in testing another library, in the context of this course, you could try installing and running a couple examples from Andreas Schlegel's ControlP5 library which will be used in both weeks 2 and 3:

http://www.sojamo.de/libraries/controlP5/

Also, and maybe this is too obvious, you do need to restart the Processing IDE for it to recognize new libraries placed in the sketchbook/libraries folder.  If that's been tried already, and the library is still not available, then it really is a bug with the Processing IDE.

So far, it's the only library that has given me such error. In particular,
I had already tried ControlP5 before week2, and it is always imported
correctly. Also, yes, restarting the PDE does not help.

However, I do get a problem when running sketches using controlP5
(_any _sketch using controlP5). It is a problem that occurs regard-
less the sketch. I wonder if other ubuntu users are experiencing any
strange behaviours in this context.



One more thing, concerning sketch drawingToolExtended, which is
included in the material of week2. When randomX, or randomY are
greater than zero, then lines are drawn even if one clicks within the
GUI area (even while one is changing the value of another control).
The reason is that lines are being drawn in the whole of the canvas
(which happens already from sketch drawingTool).
This can be fixed by adding an if in function drawLine(), as follows:

  if( GUI_WIDTH <= pmouseX ){
    line(x1, y1, x2, y2);
  }


--j

Jesus, that's a nice fix for that "bug" in the software.  Also, you may want to check out the filter portion of the extended tool, there is a bug to be fixed there as well.  Right now it is calling the filter on the entire application window, including the GUI.  If you use get() in combination with a PImage and then apply the filter to the PImage and then display that over the canvas area there is a way to solve the filter bugs. 

That's right. The bug is most noticeable with the ERODE filter, near the
right-hand side border of the GUI area. Thanks for the tip and the hint.

Yes, I tried that too. Didn't work.