Mystique theme logo fail

So I’ve just installed WordPress on a brand new host and I installed a theme called “mystique” by digitalnature. I want to customize this theme and I loaded a logo (via the “Mystique settings” menu) for It’s banner but the image won’t load correctly. Here’s an example (http://raikko.zzl.org).
I’ve tried to load several images and I’ve tried with 2 versions of wordpress but it still won’t load. How can I solve this? Could I edit the banner editing the CSS code? How?

Thanks and merry christmas,

Raikko