There appears to be a bug in the latest Node.java file (r7167). Here is the fix:
— Base (BASE)
+++ Locally Modified (Based On LOCAL)
@@ -153,7 +153,7 @@
// FIXME: Iterating through the children list backwards
// to avoid IndexOutOfBoundsException. This is sometimes unreliable,
// a more robust solution is needed.
-
for (int i = children.size(); i >= 0; i--){<br />
-
for (int i = children.size()-1; i >= 0; i--){<br />
Spatial child = children.get(i);
child.updateLogicalState(tpf);
}