Description
The tool failed because the specified z-unit parameter conflicts with the z-unit defined in the input raster dataset's vertical coordinate system.
Solution
If you are running the tool from the dialog, clear the z-unit parameter. The tool will use the z-unit from the input raster's spatial reference automatically.
If you are running the tool from Python, leave the z-unit parameter empty (blank). The tool will use the z-unit from the input raster's spatial reference automatically.
If the input raster's z-unit is incorrect, use the Define Projection tool to redefine its spatial reference before performing the analysis.