--- a/lisp/leim/quail.el	Mon Aug 13 10:05:53 2007 +0200
+++ b/lisp/leim/quail.el	Mon Aug 13 10:06:47 2007 +0200
@@ -309,10 +309,12 @@
     (define-key map [delete] 'quail-delete-last-char)
     (define-key map [backspace] 'quail-delete-last-char)
     (let ((meta-map (make-sparse-keymap)))
-      (define-key map (char-to-string meta-prefix-char) meta-map)
+      (when (characterp meta-prefix-char)
+	(define-key map (char-to-string meta-prefix-char) meta-map))
       (define-key map [escape] meta-map))
-    (define-key map (vector meta-prefix-char t)
-      'quail-execute-non-quail-command)
+    (when (characterp meta-prefix-char)
+      (define-key map (vector meta-prefix-char t)
+	'quail-execute-non-quail-command))
     ;; At last, define default key binding.
     (set-keymap-default-binding map 'quail-execute-non-quail-command)
     map)
@@ -336,10 +338,12 @@
 ;;; This interferes with handling of escape sequences on non-X terminals.
 ;;;    (define-key map "\e" '(keymap (t . quail-execute-non-quail-command)))
     (let ((meta-map (make-sparse-keymap)))
-      (define-key map (char-to-string meta-prefix-char) meta-map)
+      (when (characterp meta-prefix-char)
+	(define-key map (char-to-string meta-prefix-char) meta-map))
       (define-key map [escape] meta-map))
-    (define-key map (vector meta-prefix-char t)
-      'quail-execute-non-quail-command)
+    (when (characterp meta-prefix-char)
+      (define-key map (vector meta-prefix-char t)
+	'quail-execute-non-quail-command))
     ;; At last, define default key binding.
     (set-keymap-default-binding map 'quail-execute-non-quail-command)
     map)
@@ -370,10 +374,12 @@
     (define-key map [delete] 'quail-conversion-backward-delete-char)
     (define-key map [backspace] 'quail-conversion-backward-delete-char)
     (let ((meta-map (make-sparse-keymap)))
-      (define-key map (char-to-string meta-prefix-char) meta-map)
+      (when (characterp meta-prefix-char)
+	(define-key map (char-to-string meta-prefix-char) meta-map))
       (define-key map [escape] meta-map))
-    (define-key map (vector meta-prefix-char t)
-      'quail-execute-non-quail-command)
+    (when (characterp meta-prefix-char)
+      (define-key map (vector meta-prefix-char t)
+	'quail-execute-non-quail-command))
     ;; At last, define default key binding.
     (set-keymap-default-binding map 'quail-execute-non-quail-command)
     map)