I can't run Go programs anymore

This is the oddest problem I've ever encountered. I have my Go development environment set up on a Windows 2008 R2 virtual machine. I don't even restart it nor run Windows update.

Today I just realized that I can no longer run Go programs. I can successfully build and run unit tests with 'go test'. However, running any compiled Go program, (even hello world) causes a pop-up window titled 'Unsupported 16-bit application' to appear. The error message is as follows:

> The version of this file is not compatible with the version of Windows
> you're running. Check your computer's system information to see
> whether you need an x86 (32-bit) or x64 (64-bit) version of the
> program, and then contact the software publisher.

The result is the same regardless of what version of Go I use (x86/x64). Also note that I'm not using any IDE. I call go.exe to build/test from the command line.

I can't get my head around this since running 'go test' works just fine.

Any thoughts?

EDIT:

Here's the console output when I build and run the program:

build/run output

Interestingly, dumpbin suggests that indeed there's something wrong with the executable

C:\Program Files (x86)\Microsoft Visual Studio 11.0>dumpbin /headers
C:\Projects \GoPlayground\src\playground\playground.exe Microsoft (R)
COFF/PE Dumper Version 11.00.51106.1 Copyright (C) Microsoft
Corporation.  All rights reserved.
Dump of file C:\Projects\GoPlayground\src\playground\playground.exe
File Type: LIBRARY
C:\Projects\GoPlayground\src\playground\playground.exe : warning
LNK4003: invali d library format; library ignored
C:\Projects\GoPlayground\src\playground\playground.exe : warning
LNK4048: Invali d format file; ignored
  Summary
C:\Program Files (x86)\Microsoft Visual Studio 11.0>

And here's the full source code:

package playground
import "fmt"
import "playground/another"
func main() {
	fmt.Println("Hello world!")
	fmt.Println(another.Foobar(2))
}
-------------------
package another
func Foobar(i int) int {
	return i + 1
}

EDIT2:

I've reinstalled Go twice with no effect.

> The Go Programming Language Specification
>
> Program execution
>
> A complete program is created by linking a single, unimported package
> called the main package with all the packages it imports,
> transitively. The main package must have package name main and declare
> a function main that takes no arguments and returns no value.
>
> func main() { … }
>
> Program execution begins by initializing the main package and then
> invoking the function main. When that function invocation returns, the
> program exits. It does not wait for other (non-main) goroutines to
> complete.

Use package main, not package playground. For example,

playground.go:

package main
import (
	"fmt"
	"playground/another"
)
func main() {
	fmt.Println("Hello world!")
	fmt.Println(another.Foobar(2))
}

playground/another.go:

package another
func Foobar(i int) int {
    return i + 1
}

Output:

<pre>
Hello world!
3
</pre>
1: http://golang.org/ref/spec
2: http://golang.org/ref/spec#Program_execution