When I run mongorestore with a directory that doesn't exist, I get an error that surfaces way more than I need to know.

mongorestore -d test
2016-02-23T11:08:36.978-0500	using default 'dump' directory
2016-02-23T11:08:36.978-0500	Failed: can't create ActualPath object from path dump: stat dump: no such file or directory

Ideally we would just say "no such file or directory" plus some helpful direction on what might be wrong. The ActualPath exposes implementation details that nobody needs to debug this kind of error.