I've been using this plugin for a long time, and I haven't installed or activated anything lately, or even deactivated.
All I've been doing was my daily backup.

Today my site front page got blank, with only the light green background, Como Dinheiro Website - Click here to access. I disabled the sef in global configuration and everything started working again.

When I opened the error log file, look what I got:

PHP Fatal error: Call to undefined method stdClass::set() in /home/lucrebem/public_html/components/com_sef/joomsef.php on line 387

This is a bug, you should offer support to this kind of thing even if for free members, how can I become a payed member if I'm using something buggy that only can be solved if I pay?