I just uploaded the latest version 2010-05-20 v4.0 and noticed that all links are broken as for some reason the pages extentions are not correctly being called. An example is when clicking the Save button on index.php you are redirected to:
http://mydomain.com/xmlsitemap/index.Note: xmlsitemap is the folder in which this script resides on my server.
Note: mydomain.com was inserted by me as to not disclose my actual domain.
Also, using any of the top links also causes this problem as such: