I follwed the instructions and created the sitemap.xml and sitemap.xml.gaz files in the root directory and chmod to 666.
I activated the plugin and it throws up a dialog box to open the plugins.php file:
"Plugins.php
You have chosen to open"
I can no longer access the plugins page and have to manually delete the google plugin directory to be able to access the plugins page again.
I have clear cache and cookies in my browser.
Any ideas?