Fix typo.

lisp/org-attach.el

@@ -155,7 +155,7 @@ If the directory does not exist and CREATE-IF-NOT-EXISTS-P is non-nil,
 the directory and the corresponding ID will be created."
   (when (and (not (buffer-file-name (buffer-base-buffer)))
 	     (not (file-name-absolute-p org-attach-directory)))
-    (error "Need absolute `org-attach-directory' to attach in bufers without filename."))
+    (error "Need absolute `org-attach-directory' to attach in buffers without filename."))
   (let ((uuid (org-id-get (point) create-if-not-exists-p)))
     (when (or uuid create-if-not-exists-p)
       (unless uuid