emacs marmalade: "Cannot open load file", "package"

I got this message when I installed the latest emacs (26) from homebrew, and ran it. The problem was that OS X comes with a really old emacs (22). That was what was running when I ran emacs.

I assume that the new emacs wasn't linked in my current terminal. I fixed this problem by just opening a new terminal and running emacs from there.

Sounds like your version of Emacs does not come with library package.el. Does M-x find-library package find it? If not, you can try downloading it from the web (maybe start with Emacs Wiki), and then putting it in your load-path.

But even in that case it might not work with your Emacs version.