Estou passando por algo parecido meu log retornou isso, não sei.
line 1730 of /lib/tablelib.php: coding_exception thrown
line 187 of /lib/tablelib.php: call to table_dataformat_export_format->__construct()
line 171 of /lib/tablelib.php: call to flexible_table->export_class_instance()
line 105 of /mod/feedback/classes/responses_table.php: call to flexible_table->is_downloading()
line 70 of /mod/feedback/show_entries.php: call to mod_feedback_responses_table->__construct()
×Output buffer: <script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>