error on line 5 at column 243: xmlns:schemaLocation: 'http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.

If you have this error:

error on line 5 at column 243: xmlns:schemaLocation: 'http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd' is not a valid URI

what you will need to do is to go to Premium SEO -> ON PAGE OPTIMIZATION -> Sitemap and set to NO and save the settings.