alright. I was mistaken.
I downloaded my desired plugins from the plugins page, I unzipped them, I copied the folders into the /plugins directory of my blog... and they don't show up on my admin interface.
After a little bit of thinking I came up with the idea that I may just have to install them from my admin interface.
There is still a problem though: if I click on the "Ereignis-Plugin installieren" link, the site that is shown to me stays blank (site address: http://www.#
What do I do now?
Edit: Maybe I should add that I deleted Spartacus, but from the admin site. And I did that because the page was blank even before that.