I won't lie to you. I am not sure what it is saying, either. When I need map data, I get it here:
http://seamless.usgs.gov/website/seamless/viewer.htm
or here:
http://seamless.usgs.gov/website/seamless/viewer.htm
I download a 1 deg. x 1 deg. block in DTED or ARCGIS and then I convert it into a USGS DEM. This file format can be read by the ATF Power Toolkit.