You may recieve this with wordpress debug on. I am getting it without debug on. I think it may be this servers error configuration. I get this on every page.
Notice: Undefined index: page_id in /[path]/wp-content/plugins/spectacula-page-widget/spec-page-widget.php on line 221
This is what I did for myself.
LINE 221 Fix:
if (isset($option['page_id']) && $option['page_id'] > 0 && $option['hide_toggle'])
WP Version 2.9.2 not 2.9.3