[keycloak-user] CUstom authentication flow

[Tech @ PSYND]

Dear experts,

I'm working with version 1.9.4 of the product, I'm developing a couple 
of custom forms that should be integrated into an authentication 
workflow.

Following the example integrated into the product:
1) I compiled the "org.keycloak.examples.authenticator"
2) I copied the "secret'question.ftl" and "secret'question'config.ftl" 
files into the keycloak/themes/keycloak/login and 
keycloak/themes/base/login
3) I moved the generated jar file 
"authenticator-required-action-example.jar" into keycloak/providers
4) I opened the admin console, I create a new flow consisting of 
"Username and passowrd" and "Secret-question".

I try to login with a user and the error message that I get is:

15:36:26,319 ERROR 
[org.keycloak.forms.login.freemarker.FreeMarkerLoginFormsProvider] 
(default task-15) Failed to process template: 
org.keycloak.theme.FreeMarkerException: Failed to process template 
secret-question-config.ftl

That is compatible with what I found here: 
https://issues.jboss.org/browse/KEYCLOAK-2534

But I copied the files in the correct position: what else could cause 
such error?

Thanks