Avatar in Header

[joeboo]

I've tried almost everything. I searched around here as well, but the modifications here involving the avatar in the header always create some problem. It either displays custom avatars only, or it displays custom and preselected avatars, but now you can get a custom avatar because it says "Invalid url".

Can anyone help me out? I wish to add the avatar in the header without any problems. I would greatly appreciate it. Cheers