Regenerate the sitemap when you change the content of your blog

Hi, sorry for my bad english. A few days ago, the plugin non working for auto-regeneration.

I read this message:
Your sitemap is being refreshed at the moment. Depending on your blog size this might take some time!
Due to limitations of the WordPress scheduler, it might take another 60 seconds until the build process is actually started.

What can I do?

Regards

http://wordpress.org/extend/plugins/google-sitemap-generator/