diff --git a/clients/web/js/index.js b/clients/web/js/index.js
index 71eed55..6127906 100644
--- a/clients/web/js/index.js
+++ b/clients/web/js/index.js
@@ -23,7 +23,7 @@
 
 vanadium.init(vanadiumConfig, function(err, rt) {
   if (err) {
-    if (err instanceof vanadium.errors.ExtensionNotInstalledError) {
+    if (err instanceof vanadium.verror.ExtensionNotInstalledError) {
       return vanadium.extension.promptUserToInstallExtension();
     }
     return displayError(err);