Set up 3 new EC2 instances.
Installed membase from http://builds.hq.northscale.net/latestbuilds/membase-server-community_x86_1.6.5.deb
Setup 1024mb membase bucket on 10.112.34.115 via web interface
Had other two instances join cluster
Saw that the 2 new instances needed to be rebalanced
Clicked rebalance and got: "Rebalance failed. See logs for detailed reason. You can try rebalance again."