Update: I uploaded the SP-Studio files to a new server (well.. actually it is an old server, the one with this community). But the domain does not link to it and I have no idea where the problem might be. I contacted the support of my Host and hope they will be able to help me.
Anyway, you can build again! http://www.planearium.de/sp-studio/
The save button does not work yet, so you have to save the pictures by making a screenshot.
EDIT: The Domain works again, only the save button seems to make problems. I will have a look at this this evening.