I need help.

In my Wincustomize site I get messages from visitors. There ase 'remove' button. But if I want to delete messages nothing happens. I don't get any warning or fault.
One of that is spanish. I don't understand but It is on top of my list.

My question, how can I delete that message.

I start: I search this wallpaper: https://www.wincustomize.com/skins.aspx?skinid=17211&libid=13 . Unfortunatelly user isn't active. Does somebody what it is?