cbrestore Exception

[calvin]

hi,

I need import the membase backup data to the new membase cluster
from three single membase cluster(single node each), there is a
exception raise below

[root@dev bin]# ./cbrestore -a -p 11213 /root/backup/default /root/
backup/default-0.mb /root/backup/default-1.mb /root/backup/
default-2.mb /root/backup/default-3.mb
Exception in thread Thread-1 (most likely raised during interpreter
shutdown):
Traceback (most recent call last):
File "/usr/lib64/python2.6/threading.py", line 532, in
__bootstrap_inner
File "/usr/lib64/python2.6/threading.py", line 484, in run
File "/opt/couchbase/lib/python/cbrestore", line 123, in worker
<type 'exceptions.AttributeError'>: 'NoneType' object has no attribute
'interrupt_main'

env:
CentOS-6.2-x86_64bit
Python 2.6.6