org.el (org-forward-element, org-backward-element): Throw a message instead of an error

* org.el (org-forward-element, org-backward-element): Throw a
message instead of an error when trying to move from a
position where there is no element.

lisp/org.el

@@ -23155,9 +23155,10 @@ Move to the next element at the same level, when possible."
 	 (let* ((elem (org-element-at-point))
 		(end (org-element-property :end elem))
 		(parent (org-element-property :parent elem)))
-	   (if (and parent (= (org-element-property :contents-end parent) end))
-	       (goto-char (org-element-property :end parent))
-	     (goto-char end))))))
+	   (cond ((and parent (= (org-element-property :contents-end parent) end))
+		  (goto-char (org-element-property :end parent)))
+		 ((integer-or-marker-p end) (goto-char end))
+		 (t (message "No element at point")))))))
 
 (defun org-backward-element ()
   "Move backward by one element.
@@ -23183,6 +23184,7 @@ Move to the previous element at the same level, when possible."
 	   (cond
 	    ;; Move to beginning of current element if point isn't
 	    ;; there already.
+	    ((null beg) (message "No element at point"))
 	    ((/= (point) beg) (goto-char beg))
 	    (prev-elem (goto-char (org-element-property :begin prev-elem)))
 	    ((org-before-first-heading-p) (goto-char (point-min)))