Dear Sir; I am trying to creat a 2D mesh and read it in Fluent it gives me FATAL Error? is it posible to creat readable 2D mesh from ICEM in Fluent or i have to use Gambit?

You can definitely create purley 2D meshes in ICEM and write to Fluent.

You have to make sure you have LINE elements on all exterior edges of the mesh - for boundary condition application. So if you're using the automatic surface meshing (QUAD / TRI) having the bounding curves in the geometry should be enough - and you should get the LINE elements.

If you're using Blocking (HEXA) for the 2D mesh - you need to make sure you project all the bounding edges to the bounding curves.