Map making question

[Craigs]

Guys Im having trouble making and importing a map, I hope you can help me out. Im following Drunkrussians tutorial PDF creating_maps_from_srtm_data.pdf off the Prosimco site.
Everything seems to go well until I get to the Choose area dialog in the Power toolkit where instead of seeing a greyscale heightmap I see horizontal bands of black, grey, and white.
I think Im messing up when the tutorial is talking about selecting the map size in VTbuilder:

To select an area, select Area Tool/Numeric Values. I recommend entering the southwest corner in
the first parentheses at the bottom, and (1.0, 1.0) for the second. Any way you do it, ensure that this
area is 1 degree by 1 degree (since that is the only size ATF will accept).

I cant figure out what its saying to do.