Thanks for the replies guys;
Sergey, I mean the DNN-rights. Windows allows to propagate-from-parent so this is not the problem. DNN however doesn't have this option (so I can change the DNN-rights of a folder but the subfolders are not affected).
Rob, after reading your first reply I went to the forum but before registering, I read 'The Bug Tracker is not a support or trouble ticket system'.
So I decided to wait first but since there doesn't seem to be an answer, I regestered and I will post the question/remark over there. Thanks!