Problem regarding producing streamlines from surfaces in Ansys CFD post
 

I am facing a very unusual problem with the Ansys CFD post tool. I am unable to produce streamlines starting from a wing surface in the cfd post processing tool. The software attempts to calculate the streamline but simply does not produce a 3D streamline from the surface.

My guess is that there is an error in the selection of surfaces. But i have followed the same Cfd procedures on certain other geometries and it has worked for me previously. I have attached a two pictures of an experiment that has worked for me previously and the uav that I am trying to analyse for the trailing vortices generated.

It would be really great if someone can highlight my mistake in post processing. i have tried googling and asking around at a few other places and could not resolve the problem.