DUB saying my Linux exe file is "not an executable file" even though DUB built it

[WhatMeWorry via Digitalmars-d-learn]

Not a lot to work with here.  I'm a beginner Linux user.

$ dub build --force
Performing "debug" build using dmd for x86_64.
derelict-util 2.0.6: building configuration "library"...
derelict-gl3 1.0.18: building configuration "library"...
derelict-glfw3 3.1.0: building configuration 
"derelict-glfw3-dynamic"...
01_01_hello_window ~master: building configuration 
"application"...
Linking...
$ dub run
Performing "debug" build using dmd for x86_64.
derelict-util 2.0.6: target for configuration "library" is up to 
date.
derelict-gl3 1.0.18: target for configuration "library" is up to 
date.
derelict-glfw3 3.1.0: target for configuration 
"derelict-glfw3-dynamic" is up to date.
01_01_hello_window ~master: target for configuration 
"application" is up to date.
To force a rebuild of up-to-date targets, run again with --force.
Running ./bin/HelloWindow
Not an executable file: ./bin/HelloWindow





My sdl file looks like:

name        "01_01_hello_window"
description "A Simple Window"
authors     "generic"
copyright   "Copyright © 2016, generic"
license     "proprietary"
dependency  "derelict-util" version="~>2.0.6"
dependency  "derelict-gl3" version="~>1.0.18"
dependency  "derelict-glfw3" version="~>3.1.0"

targetPath  "bin"
targetName  "HelloWindow"
targetType  "executable"