Thanks jcl, I have compiled the level again with "Visibility" and "Light calculations" activated, but that does not help, see picture;

Shot at 2007-09-07
Mesh size is 0 and all parts are not passeble (it's just a hollow block).
I don't understand your remark "You're compiling in A6 mode". Is this standard in A7 or do I have to change something?