I cannot set permissions recursively to the child folders

Hello yet again,

I have a new user and I need to give her permission to use a set of folders and files. I thought it would be as simple as adding her to the permissions list, but my account does not even have permission. The only way I can add her to the folder is to give myself ownership to the folder first. This is a pain because it won't let me promote the permissions to the child objects because I don't have permission to edit the child objects. I tried to  use an account that does have permissions, but when I check the box to promote the permissions, it gives me the warning about removing explicit permissions on the child objects,and then after I click OK the box becomes unchecked. Is there a better way to do this? What am I missing?