NodeConcat - a simple file concatenation tool I wrote - did not support Windows. Since I built this tool for myself and I don't use Windows, I wasn't upset.
I received a pull request from ricknpc that added support for Windows by accounting for the differences in the Windows file system. That patch has been merged into master and the package has been updated on the NPM Registry.
So, if you need to use NodeConcat on Windows, make sure you update to version 0.2.3.