Trouble creating guest upload FTP

I’m having some trouble creating a user to use for guest uploading. I want clients to be able to connect to this FTP address and upload files to only one folder called “UPLOAD” or something. When I create the user, and login from my machine I’m not able to drop anything into those folders with a message saying that the folder that I’m trying to drop something into cannot be modified. Is there something I’m missing here? I’ve logged into the WebFTP and even turned on ALL access privileges, but it still won’t work.

Any suggestions?