Description
The input ASCII parameter file has a VRMA outside the accepted range. The vertical factor influences the total cost of moving into a cell by accounting for any vertical friction encountered. Determining the vertical cost for each cell is a two-step process. First, the prevailing vertical direction is defined by calculating the slope between each cell from the heights defined on the vertical-factor raster. This slope defines the vertical relative moving angle (VRMA). Once the VRMA is calculated, the vertical resistance to overcome the vertical factor is identified from the vertical-factor graph. Since the VRMA is a degree of slope, it can only range from -90 (going down) to 90 (going up). Your ASCII parameter file lists a VRMA of greater than 90 degrees.
Solution
Check that there are no values greater than 90 degrees in the specified ASCII vertical factor parameter file.