Well, turns out made a little slip-up with the style of the dtrace probes in mustang. Easily corrected, though. Instead of the VM flag, ExtendedDtraceProbes, the name is ExtendedDTraceProbes (note the capital T). And in the JNI entry and exit probes, it should have been (and is now) "-entry" and "-return" instead of "_entry" and "_return" (dashes instead of underscores). I've fixed up the text on my previous post, so it's fixed now, but if you referenced it before, you may want to look again.