As I told before, these crashes do not produce error logs...

I have uninstalled all Java versions on my computer, but strangely enough SH3D still starts.

EDIT
When I try a special "older" version of SH3D, it starts without problem, and slo opens previously made files. This version is the beta11-catmull-rom.jar. The grid is a bit distorted, but apart from that it works correctly. In About, it reports using Java 1.6.0_21.

Version 3.0 (official release) reports using Java 1.6.0_22 and still keeps crashing when having to deal with anything other than walls.
END EDIT