--- main/udptl.c	2012-04-02 11:34:23.000000000 +0200
+++ main/udptl.c	2012-04-02 11:33:44.000000000 +0200
@@ -670,6 +670,7 @@
 	struct ast_sockaddr addr;
 	uint16_t seqno = 0;
 	uint16_t *udptlheader;
+	struct ast_frame *current_frame, *next_frame;
 	
 	/* Cache where the header will go */
 	res = ast_recvfrom(udptl->fd,
@@ -715,6 +716,14 @@
 	if (udptl_rx_packet(udptl, udptl->rawdata + AST_FRIENDLY_OFFSET, res) < 1)
 		return &ast_null_frame;
 
+	current_frame = &udptl->f[0];
+	for (next_frame = AST_LIST_NEXT(current_frame, frame_list);
+		current_frame;
+		current_frame = next_frame, next_frame = current_frame ? AST_LIST_NEXT(current_frame, frame_list) : NULL) {
+		if (current_frame->datalen != 0 && current_frame->data.ptr == NULL)
+			return &ast_null_frame;
+	}
+
 	return &udptl->f[0];
 }