I'm getting this message when I try to resume a session:

Warning: unlink(/mydomain/public_html/generator/data/) [function.unlink]: Is a directory in /mydomain/public_html/generator/pages/class.xml-creator.inc.php on line 291

What do I need to do to correct this?

Thanks!
Make sure that you correctly defined "save sitemap to" setting (including sitemap filename)