Tassilo, thanks for reply. Then the emacs online reference http://www.gnu.org/software/emacs/elisp/html_node/Library-Search.html is very misleading where nil is used in an example, but explained as "current working directory". Using it in an example without any warning also makes me think using nil is recommended.
Bests, Shiyuan
>> It turns out that the problem is caused by another line of my .emacs file,
>>which I want to append the load-path,
>> (setq load-path (append (list nil "~/lisp") load-path))
>>if the "nil" is deleted, it works fine. But I don't understand why adding
>> the current directory to load-path messes up the loading of AUCTeX. I don't
> >have any lisp package s in my current directory.
>nil in `load-path' means `default-directory' which is usually your HOME,
>but might be redefined on a per-buffer basis, or maybe even bound
>dynamically in some code loading lisp files. I'd really refrain from
>using nil in `load-path'. Sounds like a can of worms to me...