What I did: emacs 24.3 for OS X was downloaded from http://emacsformacosx.com/, which comes with bundled org-mode version 7.9.3f.
I upgraded org-mode by following the method from here: http://orgmode.org/manual/Installation.html#Installation with the method#1 Using Emacs packaging system.
I included (package-initialize) in my .emacs profile.
Problems: I no longer can run org-babel C-c, C-e, b to export selected portion for html export.
When I run C-c C-e h h, it says "Invalid Key"
When I run M-x org-publish-project , it says "Invalid function: (......)".
Can anyone can shed some lights on the problem?