OpenNebula

I downloaded the 3.8.1 binary file for ubuntu 12.04 and intstall into ubuntu 12.10 server. After installing it with dkpg -i && apt-get install -f -y (to solve dependencies automatically). I was able to add a new host(same as frontend) using KVM,and run 9 vm on it.
However, after a while the STATUS for this host always changed to ERR.
I try to reboot oned, then is OK to monitor host and vm. However, after a while the STATUS for this host always changed to ERR again!!

I can ssh to host without passwd：
oneadmin@nebula:~$ ssh oneadmin@nebula
Welcome to Ubuntu 12.10 (GNU/Linux 3.5.0-21-generic x86_64)

• Documentation: https://help.ubuntu.com/

0 packages can be updated.
0 updates are security updates.

0 packages can be updated.
0 updates are security updates.
0 packages can be updated.
0 updates are security updates.

Last login: Sun Jan 6 10:32:48 2013 from nebula
oneadmin@nebula:~$

In the log file the following information was available:

Sun Jan 6 08:12:43 2013 [InM][I]: Command execution fail: 'if [ -x "/var/tmp/one/im/run_probes" ]; then /var/tmp/one/im/run_probes kvm 0 nebula; else
exit 42; fi'
Sun Jan 6 08:12:43 2013 [InM][I]: Permission denied, please try again.
Sun Jan 6 08:12:43 2013 [InM][I]: Permission denied, please try again.
Sun Jan 6 08:12:43 2013 [InM][I]: Permission denied (publickey,password).
Sun Jan 6 08:12:43 2013 [InM][I]: ExitCode: 255
Sun Jan 6 08:12:43 2013 [InM][E]: Error monitoring host 0 : MONITOR FAILURE 0 -

Sun Jan 6 08:12:43 2013 [HKM][D]: Message received: LOG I 0 Command execution fail: /var/lib/one/remotes//hooks/ft/host_error.rb 0 -r

Sun Jan 6 08:12:43 2013 [HKM][D]: Message received: LOG I 0 ExitCode: 255

Sun Jan 6 08:12:43 2013 [HKM][D]: Message received: EXECUTE FAILURE 0 error: -

Sun Jan 6 08:12:46 2013 [VMM][D]: Message received: LOG I 1 Command execution fail: 'if [ -x "/var/tmp/one/vmm/kvm/poll" ]; then /var/tmp/one/vmm/kvm/poll one-1 nebul
a 1 nebula; else exit 42; fi'

Sun Jan 6 08:12:46 2013 [VMM][D]: Message received: LOG I 1 Permission denied, please try again.

Sun Jan 6 08:12:46 2013 [VMM][D]: Message received: LOG I 1 Permission denied, please try again.

Sun Jan 6 08:12:46 2013 [VMM][D]: Message received: LOG I 1 Permission denied (publickey,password).

Sun Jan 6 08:12:46 2013 [VMM][D]: Message received: LOG I 1 ExitCode: 255

Sun Jan 6 08:12:46 2013 [VMM][D]: Message received: POLL FAILURE 1 -

I try the solution in http://dev.opennebula.org/issues/1041, but it's not effective.

thanks for your help!