Index: png.c
===================================================================
--- png.c	(revision 29225)
+++ png.c	(revision 29226)
@@ -782,7 +782,7 @@
 
 pcb_trace("EMPTY: %ld %d\n", png_drawn_objs, png_cam.okempty_content);
 	if (pcb_cam_end(&png_cam) == 0) {
-		if (!png_cam.okempty)
+		if (!png_cam.okempty_group)
 			pcb_message(PCB_MSG_ERROR, "png cam export for '%s' failed to produce any content (layer group missing)\n", options[HA_cam].str);
 	}
 	else if (png_drawn_objs == 0)