I tried to compile the auctex from Emacs MELPA. The version is: 11.88.4
When I first open a .tex file, compile AUCTEX, and change to "TeX-latex-mode", Emacs will work properly, the menu bar also change to latex state.
However, when I close Emacs, restart Emacs again and open a .tex file, Emacs will give:
Debugger entered--Lisp error: (error "Autoloading failed to define function TeX-latex-mode")
And auctex will not work...
It seems the problem is in autoloading certain state when initialize the auctex for a tex file.