okey ich habe die lösung die im Steam forum gesagt wird versucht:
Game not Launching?
There's an issue going on where not all files are being properly acquired from Steam. This is leading to Java shutting down when it can't find the appropriate resources. A work-around has been identified.
Install a copy of the game from the Spiral Knights website. There have been no reports of missing files through this distribution.
Copy the rsrc folder from the new installation on top of the rsrc folder in the Steam installation. Replace all files.
Try launching the game as normal.
hat aber nicht geklapt und auch wenn ich den kompleten ordner von der SpiralKnight website runterlade und in den Steam ordner reinpacke geht auch nicht.