I'm trying to use the Skyline functon in 3D Analyst. I get a general error message 999999, which doesn't help much (inputs and message attached as jpeg). The file structure is created (i.e. I end up with an empty file in my database). I've included my inputs in the attachement so you can tell me if I need to add something.
Always be sure that the point file being used is above the DEM being input. I have seen many situations where the point is below the input DEM and an error will prompt. Also I cannot see your full path, but it appears that you are exporting to the Q drive. Does the same behavior happen when you output locally?
When you get around to testing it, I would recommend trying the Add Surface Information tool to determine the height of the point on the DEM and then compare it to the inherent z elevation. This should be the most direct test to determine if the point is indeed below the surface. If it is, then you can consider whether the elevation is incorrect for the surface or if there are other issues. If it is the same, then I would recommend creating the point at the desired height again that is above the surface. Let me know if you have questions when you get off the sideline.