[Plugin: Hackadelic SEO Table Of Contents] Error messages

Hi! It seems this plugin is no longer maintained, since the newest post is 1 year ago. But it’s exactly what I need, so I’m hoping someone can help me out. ??

I’m getting these error messages in the error log of the website I’m using it on. The plugin still works, but it makes me nervous. Thanks!

[04-Feb-2011 01:02:08] PHP Fatal error: Call to undefined method HackadelicTOC::signature() in /home/alan/public_html/wp-content/plugins/hackadelic-table-of-content-boxes/hackadelic-toc.php on line 290

[04-Feb-2011 02:16:11] PHP Warning: include(common/xsig.php) [function.include]: failed to open stream: No such file or directory in /home/alan/public_html/wp-content/plugins/hackadelic-table-of-content-boxes/hackadelic-toc.php on line 310