Unexpected error

I have got an Asus Eee PC 1005PE, with windows 7 installed.
I have installed the Graphing Calculator 3D Free-Edition.
After start the Graphing calculator, when I try to graph a function such z = x + y, a message box pops up with the title:
Draw error
and the following message:
Unexpected Error: javax.media.j3d.IndexedGeometryArray.setCoordIndicesRef([I)V
¿May you tell me what is the problem, and how I can solve it?
Thanks.

That error happens when there is an older version of Java3D installed in your computer.
Please uninstall Java3D from your computer and that should fix it.