Mongostats not working with Authentication enabled

I upgraded an existing server to the 2.0 code. When authentication is enabled, I am unable to run mongostat. I get "error:
>

" even when using a correct username/password for an admin account. That is, I can login to admin db with the mongo cli with a given set of credentials but can not run mongostat with the same credentials.

If I turn off authentication, I'm able to run mongostat.