Sebastian: the translation you've done seems to be very weird: I seem to have many words in German or so ...
Now the problems:
- you have the setting "Use dropdown for locations" for Events Manager Extended on. I've disabled it, so now you can insert new locations with events.
- for the image upload: the size is set to a max of 204800 bytes (or: 200 KB), seems very low to me ... try increasing that (I increased it to 2MB for you)
- for the missing details: you never mention the shortcode #_NOTES anywhere in the format settings, so of course the details are never shown. I've changed the setting "Default single event format" to include this (which is called "Standardformat für eine Terminseite" in your page anyway) but you should change this to your liking.
So to summarize: you have no problems at all, just settings you need to check.