[Plugin: Google XML Sitemaps] Plugin Does not have a valid header

Hi All,

First time posting a question.
I am WP 3.0 on a subdomain of a site.

When I try to install the Google XML Sitemap Generator plugin I get the following error,

“This plugin does not have a valid header”

Any ideas on how to resolve?

Thanks!

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