couchbase error on 'grunt build' - dlopen no suitable image found

Doing grunt build of a project that uses couchbase on a Windows machine works with no problems at all.

However doing the same on a Mac OS machine throws the following error:

/Users/tiagoalves/workspace/projects/myproject/node_modules/myproject-clients/node_modules/couchbase/lib/binding.js:17
      throw e;
            ^
Error: dlopen(/Users/tiagoalves/workspace/projects/myproject/node_modules/myproject-clients/node_modules/couchbase/prebuilt/win/x64/couchbase_impl.node, 1): no suitable image found.  Did find:
    /Users/tiagoalves/workspace/projects/myproject/node_modules/myproject-clients/node_modules/couchbase/prebuilt/win/x64/couchbase_impl.node: unknown file type, first eight bytes: 0x4D 0x5A 0x90 0x00 0x03 0x00 0x00 0x00
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at bindings (/Users/tiagoalves/workspace/projects/myproject/node_modules/myproject-clients/node_modules/couchbase/node_modules/bindings/bindings.js:74:15)
    at tryLoadBinding (/Users/tiagoalves/workspace/projects/myproject/node_modules/myproject-clients/node_modules/couchbase/lib/binding.js:13:31)
    at Object.<anonymous> (/Users/tiagoalves/workspace/projects/myproject/node_modules/myproject-clients/node_modules/couchbase/lib/binding.js:31:17)
    at Module._compile (module.js:456:26)
    at Module._extensions..js (module.js:474:10)
    at Object.Module._extensions..js (/Users/tiagoalves/workspace/projects/myproject/node_modules/grunt-mocha-istanbul/node_modules/istanbul/lib/hook.js:102:13)

I have been trying to solve this for a week now. I did a complete nodejs and npm reinstall, same for brew and so on... What is happening?