Hey Luciano,

I am really sorry for the delay of this reply as it is actually a public day off for us here. Hm, this error seems to be coming from a template override in your Joomla template.

If you try to rename the folder /templates/jsn_decor_pro/html/mod_easyblogwelcome to a different name, do you still hit any errors?

We are no longer using the variable $isLoggedIn in the module's template file and you need to contact Joomlashine and get them to update their codes in the template.

Anyway, if you need us to fix this, please provide us with the back end and FTP access and we'll be glad to help you to fix the template override.