drupal unserialize error when editing a node

This is returning nothing on a google search and driving me nuts.  basically, when editing a node that utilizes cck fields and a custom module that displays a graph, I get these errors when I click save:

warning: unserialize() [function.unserialize]: Node no longer exists in /var/www/includes/cache.inc on line 33.
warning: unserialize() [function.unserialize]: Node no longer exists in /var/www/includes/cache.inc on line 33.
warning: unserialize() [function.unserialize]: Node no longer exists in /var/www/includes/cache.inc on line 33.
warning: unserialize() [function.unserialize]: Node no longer exists in /var/www/includes/cache.inc on line 33.

I will get this fixed sooner or later and update it here....