Umg! Buildism crashed

[Fat_Sacks]

java.lang.NullPointerException
net.buildism.object.Joint.getProp(Joint.java:153)
net.buildism.c.b.b(DefaultInputProcessor.java:372)
net.buildism.f.p(Main.java:687)
net.buildism.MainApplet.run(MainApplet.java:220)
java.lang.Thread.run(Unknown Source)

I got this error when it crashed.

[Aaron]

That happens to me after about 5 mins of gameplay.