"Intersection failed with this error: TriangulationFail

Hello, I used the Surface option in the Borehole to create top surface matching with the Filed data from the Laser image in .dxf format. But the message I received on clicking the Mesh tab is as follows. "Intersection failed with this error: TriangulationFail
The following objects are producing non valid shapes: (Error) Parents are not found". I tried using NURBS conversion with different combinations of X and Y but could not get through. I\Can someone help?