The article says, that the Plugin ScrapBukkit is currently inactive. So now, it's impossible for me to teleport and so on. Is there a chance to delete the Plugin, so I can use the original commands? Or do I have to wait for a stable version of ScrapBukkit? Because I could not delete the scrapbukkit.jar in the plugin folder cause it said, I had not the permission to do that.
You couldn't delete the scrapbukkit.jar because your server was running. You generally shouldn't do any operations on server files while it's up.
No, my FTP client says, I had not the permission to execute the deleting, even if I turn the server off. Is it possible to use the standard commands if I delete the Scrapbukkit.jar?
Check the permissions on the file, ls -l in linux, which I'm kinda assuming you're using. You probably put the .jar there as another user or root. You could either login as root, or use sudo to remove the file.
I see an updated version of ScrapBukkit available here: http://ci.bukkit.org/job/dev-ScrapBukkit/ Moved to appropriate forum.