diff --git a/core/tfrpc.js b/core/tfrpc.js
index ac976c1e..f1bf48ec 100644
--- a/core/tfrpc.js
+++ b/core/tfrpc.js
@@ -39,9 +39,9 @@ function send(response) {
 
 function call_rpc(message) {
 	if (message && message.message === 'tfrpc') {
-		let method = g_api[message.method];
 		let id = message.id;
 		if (message.method) {
+			let method = g_api[message.method];
 			if (method) {
 				try {
 					Promise.resolve(method(...message.params)).then(function(result) {
@@ -53,7 +53,7 @@ function call_rpc(message) {
 					send({message: 'tfrpc', id: id, error: error});
 				}
 			} else {
-				throw new Error(message.method + ' not found.');
+				send({message: 'tfrpc', id: id, error: `Method '${message.method}' not found.`});
 			}
 		} else if (message.error !== undefined) {
 			if (g_calls[id]) {