npm run build gets error

> ./hex-build.js

'.' is not recognized as an internal or external command,
operable program or batch file.
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! bitcoinhex@0.0.1 build: `./hex-build.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the bitcoinhex@0.0.1 build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
