Strange thing with skeinforge

[lionel...@gmail.com]

Hi all,

I started calibrating my reprap and I have a strange problem. When printing this part I end up with an extra wall, but the shape is otherwise fine (and actually quite nice). I tried with two versions of skeinforge and the results are the same.
For the details, this wall is the first line that is being drawn when the extruder passes from the small part to the large one. The small part is unaffected by this problem and comes out fine.

Here is a picture of the large piece when printed out. Any idea?

Lionel