[zovs66]

The fellow posted this:

"Here is the fixed script. Somewhere between line 190 and 200 is where the bug is, where it calls the heightmap files. Adjusting one of the "arrays" to allow an extra digit fixed it.

Do note that I cannot vouch it being bug-free, I am not proficient in Perl."

and:

"Do note also there is also an off-by-one bug when entering the longitude in the script. Still trying to debug it when I have the free time.
For example, entering N39.60354930809638, W105.0732811510434, increment longitude by 1, change it to W106.0732811510434
Mine created the map squarely right into where I wanted it, and made a map out of that area."

I have downloaded his script, but I don't have UNIX / LYNIX to run it.

So its sits on my hard drive.