diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index 7668ec2..8486863 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -1287,7 +1287,7 @@
 	unsigned int where;
 
 	cur_arg = *orig_arg;
-	expr = sample_parse_expr((char **)args, &cur_arg, px->conf.args.file, px->conf.args.line, err, &px->conf.args);
+	expr = sample_parse_expr((char **)args, &cur_arg, px->conf.args.file, px->conf.args.line, err, &px->conf.args, NULL);
 	if (!expr)
 		return ACT_RET_PRS_ERR;