When you try to take ownership of a file or folder, you may simply get a message saying something to the effect of “unable to take ownership”. If this happens, log onto the machine hosting the file / folder (assuming it’s shared, and not local). Then open a command prompt as Administrator (right click -> Run as Administrator), cd to the folder with the problem and use the following command:
takeown /F foldername
Then try to take ownership of the folder the usual way, and set the NTFS permissions.
You may then find that you can’t propagate the permissions to subfolders. To do this, run the following command (after you did the above steps):
takeown /F * /r
This will take ownership of all the subfiles and subfolders in the directory. You can then go ahead and change the permissions as usual.