You're not overlooking anything...we're moving the Forums to a new server, so the files are all locked down. We're hoping to have the transfer complete over the weekend, and you'll be able to upload images again at that time. Sorry for the inconvenience...
The server move finally happened last night. We are in the process of updating some of the upload files so images/avatars, etc., can be uploaded again. It should be fixed sometime today. Thanks for the patience!
The server switch is complete and the writable files are operational. Avatar and general image uploads should be good to go. Thanks for the patience guys!