Hi Cosmin, to extrude a 3D sketch, you need to pick a plane or edge to specify the extrusion direction. To do that, pick in the field underneath the extrusion type list and then select an edge or plane from your model.
I made a screen capture but Internet Explorer isn't letting me upload it, so let me know if you need me to explain it a little more.
...it's working .....i had the plane hidden. Thank you .