Index: lisp/rfc2231.el
===================================================================
RCS file: /usr/local/cvsroot/gnus/lisp/rfc2231.el,v
retrieving revision 7.25
diff -u -r7.25 rfc2231.el
--- lisp/rfc2231.el	24 Apr 2008 04:19:20 -0000	7.25
+++ lisp/rfc2231.el	5 May 2008 20:13:34 -0000
@@ -217,10 +217,11 @@
       (insert value)
       (goto-char (point-min))
       (while (search-forward "%" nil t)
-	(insert
-	 (prog1
-	     (string-to-number (buffer-substring (point) (+ (point) 2)) 16)
-	   (delete-region (1- (point)) (+ (point) 2)))))
+        (if (<= (+ (point) 2) (point-max))
+            (insert
+             (prog1
+                 (string-to-number (buffer-substring (point) (+ (point) 2)) 16)
+               (delete-region (1- (point)) (+ (point) 2))))))
       ;; Decode using the charset, if any.
       (if (memq coding-system '(nil ascii))
 	  (buffer-string)