Coding problem: $PAGE->context was not set. You may have forgotten to call require_login() or $PAGE->set_context(). The page may not display correctly as a result

• line 572 of /lib/pagelib.php: call to debugging()
• line 967 of /lib/pagelib.php: call to moodle_page->magic_get_context()
• line 1550 of /lib/weblib.php: call to moodle_page->__get()
• line 1397 of /lib/pagelib.php: call to format_string()
• line 9 of /uv_horas_examenes.php: call to moodle_page->set_title()