Forum Horde-Groupware mit Webmailer

Hello there,

I created a second calendar. Now I wan't to open the external URL in my browser I get an "404 error".
I noticed that the URL contains a "%2F" instead of a "/". I changed the "%2F" to a "/" and the error was eliminated.
But there is still no content.
My standard calendar works fine but I don't know why the other calendar is not generated.
Can anyone help me?

(sry for my english :/ )