Developer hint: /bitnami/moodle/theme/labformativo/renderer.php should be renamed to /bitnami/moodle/theme/labformativo/renderers.php.
See: http://docs.moodle.org/dev/Output_renderers#Theme_renderers.
line 796 of /lib/outputlib.php: call to debugging()
line 699 of /lib/outputlib.php: call to theme_config->__construct()
line 7429 of /lib/moodlelib.php: call to theme_config::load()
line 685 of /lib/classes/user.php: call to get_list_of_themes()
line 845 of /lib/classes/user.php: call to core_user::fill_properties_cache()
line 50 of /login/signup_form.php: call to core_user::get_property_type()
line 214 of /lib/formslib.php: call to login_signup_form->definition()
line 317 of /lib/authlib.php: call to moodleform->__construct()
line 80 of /login/signup.php: call to auth_plugin_base->signup_form()