Unable to change sitemap settings

Hi,

I am unable to change the sitemap settings.

For example, if I deselect “Add images to XML Sitemap.” on the XML sitemaps page, as soon as I click “Save XML sitemaps settings” the old settings reappear. The same thing happens with all the other settings, such as ‘ping Google’

I am trying to do this as since using the new sitemap generating facility my pages seems to have plummeted in the rankings (over 1000 places i some cases!) and I am wondering if it is due to Google having both the old and the new sitemaps to look at??

Any thoughts on that would be most appreciated!!

Many thanks,

Glyn