Download has a blank page

Hello,
i install the plugin and create a categorie.
Then i add a new download for this categorie.
It works, but when I click the download I will be forwarded to a blank page.
If you look right, you can see that the download page is very short, but then disappears and only the blank page is displayed.

My Site: https://borat.likesyou.org/cmdownloads
And my the blank Site: https://borat.likesyou.org/cmdownloads/test/

I hope someone can help me.
And sorry for my bad english, but im german.

greets