Rebalance_out failed during viewquery test

I have a test that loads 90k docs, and simultaneously runs view queries.
The last step is to rebalance out the nodes while the queries are still running.
However the rebalance fails and I picked up the following excerpt from the logs:

{none,<<"Rebalance failed. See logs for detailed reason. You can try rebalance again.">>}

[ns_server:info] [2012-02-09 5:41:47] [ns_1@10.1.2.30:ns_config_events:ns_node_disco_conf_events:handle_event:56] ns_node_disco_conf_events config all
[ns_server:info] [2012-02-09 5:41:47] [ns_1@10.1.2.30:ns_config_rep:ns_config_rep:handle_info:181] Pushing config
[ns_server:info] [2012-02-09 5:41:47] [ns_1@10.1.2.30:ns_config_rep:ns_config_rep:handle_info:183] Pushing config done
[error_logger:error] [2012-02-09 5:41:47] [ns_1@10.1.2.30:error_logger:ale_error_logger_handler:log_report:72]
=========================CRASH REPORT=========================
crasher:
initial call: couch_db_set:init/1
pid: <0.22757.8>
registered_name: []
exception exit: {noproc,
{gen_server,call,
[<0.25731.8>,

{add,<0.25744.8>}

,infinity]}}
in function couch_db_set:init/1
ancestors: [<0.22733.8>,<0.22732.8>]
messages: []
links: [<0.22733.8>,<0.24571.8>]
dictionary: [{random_seed,{8236,26623,17360}}]
trap_exit: false
status: running
heap_size: 121393
stack_size: 24
reductions: 44019
....