Forever fails when exit code == -1

That is what I am getting:

``` events.js:72
        throw er; // Unhandled 'error' event
              ^
Error: spawn OK
    at errnoException (child_process.js:980:11)
    at Process.ChildProcess._handle.onexit (child_process.js:771:34)
```

when using:

`setTimeout(function(){process.exit(-1)},3000);`

Is this by design?

I'm using forever 0.10.11 on Windows 7 64
