Hi everybody,
my first question in this forum, I hope I don't mess up:
After upgrade to 5.4.1 there is a problem with the file manager. After hitting the upload button, the file manager shows a blank screen; url is http://[my site name]/index.php/tools/required/files/importers/single

However, if I go back, the file is uploaded sucessfully. Problem is: I can't change file sets. I can create a new file set and the file will be in that new file set. But I cannot put it in existing file sets.
When I use the multiple file uploader, I don't get the blank page but the regular pop up with "assigne file sets, edit properties, close window" after the successful upload. When I click on "assigne file sets" or "set properties", nothing happens. Only the "close" button works.
Is there anything wrong in my /tools/files/importers directory with the *.php 's? Or what else could be the problem?

Thanks in advance.