latex 에러메시지(! Package inputenc Error)

아직 리눅스 초보구요. 오픈수세 11-2를 쓰고 있습니다. kotex을 깐 뒤 학위논문을 emacs로 별문제 없이 잘 쓰고 있는데
갑자기 다음과 같은 에러메시지가 뜨네요.

! Package inputenc Error : Keyboard character used is undefined
(inputenc) in inputencoding 'utf8'.

무엇이 문제인지 가르쳐 주세요ㅜ^^
참고로 저의 .emacs를 첨부하였습니다.

(require 'cl)
(when enable-multibyte-characters
(set-language-environment "Korean")
(setq-default file-name-coding-system 'utf-8)
;; comment out if you use 3 bulsik
(setq default-korean-keyboard "3")
(setq default-input-method "korean-hangul3")
(setq input-method-verbose-flag nil
input-method-highlight-flag nil)
;;;; give highest priority to euc-kr
(prefer-coding-system 'utf-8)
(set-default-coding-systems 'utf-8)

(add-hook 'quail-inactivate-hook 'delete-quail-completions)
(defun delete-quail-completions ()
(when (get-buffer "*Quail Completions*")
(kill-buffer "*Quail Completions*")))
;(set-selection-coding-system 'euc-kr)
(set-selection-coding-system 'utf-8)

;;(unless window-system
;;(menu-bar-mode -1)
;;(set-keyboard-coding-system 'nil)
;;(set-terminal-coding-system 'euc-kr))

;; Hangul Mail setting
(setq-default sendmail-coding-system 'euc-kr)

;; For use of `emacs -nw' in Korean terminal emulator
(if (and (null window-system) (null noninteractive))
(progn
(set-keyboard-coding-system 'utf-8)
(set-terminal-coding-system 'utf-8)))

;; hangul printing for ps-mule.el
(setq-default ps-multibyte-buffer 'non-latin-printer)

;; turn off C-h during input
(eval-after-load "quail"
'(progn
(define-key quail-translation-keymap "\C-h"
'quail-delete-last-char)
;;(define-key quail-translation-keymap "\C-?"
;; 'quail-translation-help)
(define-key quail-translation-keymap "\C-?"
'quail-delete-last-char)
))

;; The default coding system of the dired buffer is utf-8.
(add-hook 'dired-before-readin-hook
(lambda ()
(set (make-local-variable 'coding-system-for-read) 'utf-8)))
)

(defun unicode-shell ()
"Execute the shell buffer in UTF-8 encoding.
Note that you'll need to set the environment variable LANG and others
appropriately."
(interactive)
(let ((coding-system-for-read 'utf-8)
(coding-system-for-write 'utf-8)
(coding-system-require-warning t))
(call-interactively 'shell)))