Make sure you are providing your public key and that is in the proper format, sometimes some key generators confuse the format, it should be something like this:
ssh-rsa AAAAB ... LOTS of other chars== comment@something.usually
You can just copy and paste it into the box in your profile instead of uploading the file.
Remember - it must be only your public file, either an RSA or DSA key is fine. Your private file stays private. So if both public and private are in same file, this will not work.