Error in smart Crawl

Hi Guys and Girls
I am getting this error on page save, it isn't actually effecting the ability to save just a tad annoying.
Fatal error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 20480 bytes) in /home/icartist/public_html/wp-content/plugins/wpmu-dev-seo/includes/external/simple_html_dom.php on line 1497

Regards
Jaxom