I am trying to use MELPA to install the emacs package "multi-term". When I do package-install multi-term, I get "http://melpa.org/packages/multi-term-20141203.1658.el: Not found". However, a more recent version http://melpa.org/packages/multi-term-20150220.1320.el is on MELPA. Why is emacs not installing this version?
This can happen if a package is updated in MELPA while you have an old list of packages cached locally.
Update your local package list with M-x package-refresh-contents and try again. This should sync your local package list with MELPA, and installing your package should work.