Hi Lucianmli,
That doesn't sounds quite right. Can you provided some details of the troublesome jars and we will investigate.
HEAD is always moving and is designed to represent the most current RM development stream. This means things may or may not be stable. I'll investigate whether it's possible to mirror publicly the 2.1.a community tagged archive. That would be the best community code base to work from, although for RM I would highly recommend considering an enterprise licence.
Thanks,
Roy