"invalid ELF header" when using the nodejs "ref" module on AWS Lambda

I've just uploaded a zip to AWS Lambda which included the "ref" (http://ift.tt/1Jfa8da), which is needed to validate an iOS Game Center authentication token (How to authenticate Game Center User from 3rd party node.js server).

Unfortunately invoking it results in the "invalid ELF header" error,

{
  "errorMessage": "/var/task/node_modules/ref/build/Release/binding.node: invalid ELF header",
  "errorType": "Error",
  "stackTrace": [
    "Module.load (module.js:356:32)",
    "Function.Module._load (module.js:312:12)",
    "Module.require (module.js:364:17)",
    "require (module.js:380:17)",
    "bindings (/var/task/node_modules/ref/node_modules/bindings/bindings.js:76:44)",
    "Object.<anonymous> (/var/task/node_modules/ref/lib/ref.js:5:47)",
    "Module._compile (module.js:456:26)",
    "Object.Module._extensions..js (module.js:474:10)",
    "Module.load (module.js:356:32)",
    "Function.Module._load (module.js:312:12)"
  ]
}

This has been developed on a 64bit Macbook Pro running Yosemite which has no problem running the code locally. Googling around for "invalid ELF header" has yielded little to know relevant results and I'm really not sure where to go from here. Would I be better asking this in a node.js area, or is this the relevant area, because it might be an issue with the platform?