Created using ANSYS 16.1
Sometimes when importing a geometry (especially one that you did not create yourself) there are certain errors given by DesignModeler. In this tip, the specific error is when the geometry imported is incomplete or specifically, not a surface and is instead a series of edges.
At this point, you should have a surface from the edges you imported into Design Modeler. If you see that you have created several edges along one surface and want to have just one edge you can combine the edges in the Meshing step by using virtual surfaces.
Doing this should combine all of the edges you want under a virtual body. This will make it easy to complete the meshing and for future steps in your simulation.