Cannot Package Visual...'PBIVIZ Package' Errors Out

Question

I've been developing a Power BI visual and it works fine using pbiviz start and the Power BI site's developer visual. So I'm ready to package it. I tried pbiviz package, but get these errors:

C:\Users\MARC_000\Desktop\OrdinalScatterChart>pbiviz package
module.js:472
    throw err;
    ^
Error: Cannot find module './nodejs/NodejsStreamInputAdapter'
    at Function.Module._resolveFilename (module.js:470:15)
    at Function.Module._load (module.js:418:25)
    at Module.require (module.js:498:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (C:\Users\MARC_000\AppData\Roaming\npm\node_modules\powerbi-visuals-tools\node_modules\jszip\lib\object.js:11:32)
    at Module._compile (module.js:571:32)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:488:32)
    at tryModuleLoad (module.js:447:12)
    at Function.Module._load (module.js:439:3)

Any idea why I'm getting these and how to fix my problem?