Problem with Bezier curve to extrude (3d > 2d)

Hi, m basically Max and Maya User, and now days trying to work with blender so m new for it and blenderartist too! so m not sure this is the right place to post a question or not!!
i just need a lil help.
in Blender i created a shapes using bezier curve, then for extrude i just changed the curve types 3D to 2D.
but when i press it all curves points are coming to same position. like one single line!!
I dont know what m doing wrong!

can anyone correct me pls!