As per https://github.com/joyent/node/wiki/Api-changes-between-v0.8-and-v0.10 , path.resolve & path.join will now throw an error on non-string input (previously they ignored it).
I was just trying to build TypeScript (which uses jake) with the latest Node v0.10 and hit issues. mkDirP in ./lib/file.js doesn't initialize currPath, so the first call to path.join with it (https://github.com/mde/utilities/blob/master/lib/file.js#L285) throws an exception now.
Simply changing the currPath declaration 10 lines earlier to ' currPath = "" ' (an empty string) fixed the issue for me. Not sure any other areas you might get bitten by this!
Issue #6 Node 0.10 changes, path.join doesn't accept undefined as input
Fixed in 0605188, pushed to NPM in v0.0.20.