Index: apps/app_dial.c
===================================================================
--- apps/app_dial.c	(revision 183627)
+++ apps/app_dial.c	(working copy)
@@ -2009,14 +2009,14 @@
 	parse = ast_strdupa(data);
 	AST_STANDARD_APP_ARGS(args, parse);
 
-	if (!ast_strlen_zero(args.sleep) && (sleep = atoi(args.sleep)))
+	if (args.argc > 1 && !ast_strlen_zero(args.sleep) && (sleep = atoi(args.sleep)))
 		sleep *= 1000;
 
-	if (!ast_strlen_zero(args.retries)) {
+	if (args.argc > 2 && !ast_strlen_zero(args.retries)) {
 		loops = atoi(args.retries);
 	}
 
-	if (!args.dialdata) {
+	if (args.argc != 4 || !args.dialdata) {
 		ast_log(LOG_ERROR, "%s requires a 4th argument (dialdata)\n", rapp);
 		goto done;
 	}