This is a bug. The issue is that the Makefile doesn't include sim/util/distribution/*.java in its build (oops!). I've done an SVN commit of this plus a few other bugs. If you can't get SVN, I can provide you with a revised Makefile, or a revised jar build. Sean On Nov 9, 2011, at 12:12 AM, Chris Hollander wrote: > Just a quick question... are there plans to include > sim.util.distribution in the pre-built JAR file for Mason? The classes > aren't present in the latest release. (but the source is in the actual > directory, outside of the jar file.)