node-cloudfiles is using a simple, UNIX-y test to determine if a path is absolute or relative:
if (p.charAt(0) != '/') { cb(new Error('Relative path: ' + p)); return }
There's an issue about this on GitHub. As noted there, for a workaround, replace vendor/mkdirp.js
with https://github.com/substack/node-mkdirp.