Rebalance failed after fail over a down node

Created an attachment (id=580)
diag of node A

Install ns server 1.6.0beta3.2-7 on 2 ubuntu 10.04 32bit standalone servers.
Add data to default bucket by using memslap -t 2m -T 4 -c 128 on node A.
After 2 minutes running, add node B to node A.
Rebalance (work as expected)
Shut down node B by uninstall ns server on node B
At node A server page, see node B down (as expected) and click fail over.
Click rebalance (failed). NS web console reload automatically and shows error.
Click on server page again and see "Rebalance" button is not clickable.
http://screencast.com/t/MjQ3ZTk0ZG
Capture of logs on log page
http://screencast.com/t/YTlkNzRiZ