Sure, i can help you....i will look into the fix myself directly in the source code when i have time later today.
Just realized since your domain is an IDN (Internationalized Domain Name) it will need to be PunyCode'ed. Punycode is a encoding syntax by which a Unicode (UTF-8) string of characters can be translated into the basic ASCII-characters permitted in network host names (you do this via: idn_to_ascii("www.bästalotterna.com"); ). For example, although you see the umlaut, underneath (and in your website's source code i see your domain is: http://www.xn--bstalotterna-gcb.com. A few more questions:
1. Can you provide the exact error message?
2. You mention: "In the detected path for the file there is a black question mark". Was this error in your error_log file or where exactly are you seeing this?
2. Is the problem occurring when PHP attempts to write out the sitemap.xml file whereby inside said file an XML node(s) line is attempting to prepend your host url: http://www.bästalotterna.com to your article page locations?
3. Is the path directory of your site inside a directory called bästalotterna.com? So the directory literally shows an umlaut?
We may need to try a few things since i have never quite worked with IDNs before but am very curious to get this to work.
Thanks for any extra info.