Lena are you sure this is how u're importing it
Admin CP > Styles & Templates > Download / Upload Styles > Import Style XML File > browse (select file, Open) and then click Import
If that's not how you're importing it then perhaps you need to do it like that

. Otherwise there is nothing wrong with the xml file unless u're really importing the wrong xml file?
Hope this helps

if not then do post back and we'll see what could be the problem

.