I have integrate standalone tiles in my project (for my company).
When JRun 4 stop (or I trigger the hot-deploy to reload the webapp), it will throw a NullPointerException.
After some study, the NPE should be cause by the absence of super.init(config) call in TilesServlet.java
I'll attach my one-line patch. Hope useful...
(BTW, what's the current status on standalone-tiles?)