This is a shot in the dark kind of, but has anyone here ever secretly dabbled in terrain creation, or are any of the legends from the past who have done it still lurking around here on occasion?

I've had Global Mapper for a while and thought I'd finally use some down time around the holidays to see if I could understand something of it. I've downloaded the tutorials on it I could find, but I have yet to successfully use the ers2tiff.exe tool. I always get the error message: Failed to load any input file. It might be something with the way I'm exporting data, or or something with the command line parameters I'm using. This is with the SRTM 30 arc second data for now, though I'd really like to use SRTM 3 arc second data. I've seen that it has been done, but no idea how. But for now I can't even get off the ground with the basics. If anyone can help, I'd appreciate it.