On the following system:

scriptcraft v3.2.0-2016-03-19
CraftBukkit version git-Spigot-d20369f-7fc5cd8 (MC: 1.9) (Implementing API version 1.9-R0.1-SNAPSHOT)

When executing this line in minecraft it works:
/js box0(blocks.quartz,breite,5,breite).fwd().right().box(blocks.emerald,8,1,8).up(5).left().back().times(5);

When using it in a js file, the server hangs:
this.box0(blocks.quartz,breite,5,breite).fwd().right().box(blocks.emerald,8,1,8).up(5).left().back().times(5);
The remedy is to use a for loop like this:
for (var i=0;i<anz_stock;i++) {
this.box0(blocks.quartz,breite,5,breite).fwd().right().box(blocks.emerald,breite-2,1,breite-2).up(5).left().back();
}

This seems to be related to issue #248