How to make 2 or 3 xml sitemaps in drupal for example for different taxonomies?
I suggest installing the Views Data Export module. It will allow you to create XML pages from your taxonomy and as many as you want.

I would create one view and 4 page displays with the varying filters to generate your pages.  Then change the output to XML.

I looked over the XML Sitemap, and the error you are experiencing seems to be something they are trying to troubleshoot. You can follow along there, or try some of their methods.