Sitemap generator problem

[buzdu]

What permissions and what files need to be made ​​to the Sitemap generator plugin to work properly?

I ask this because I can not get the plugin configuration page and its generation appears to me a blank page, but no error.

Root is generated sitemap.xml file but the following error:

This page contains the Following errors:

error on line 3437 at column 11: Extra content at the end of the document
Below is a rendering of the page up to the first error.