cuckoo start error ，cannot shut down 'cuckoo1'

I run cuckoo as a normal user,which is windows xp,and the host machine is ubuntu,but it show this:

'''
log file:
CuckooCriticalError: Please update your configuration. Unable to shut 'cuckoo1' down or find the machine in its proper state: The virtual machine 'cuckoo1' doesn't exist! Please create one or more Cuckoo analysis VMs and properly fill out the Cuckoo configuration!

'''

so I check my virtualbox.conf,which like this,I just copy something about:

'''

[virtualbox]
# Specify which VirtualBox mode you want to run your machines on.
# Can be "gui" or "headless". Please refer to VirtualBox's official
# documentation to understand the differences.
mode = headless

# Path to the local installation of the VBoxManage utility.
path = /usr/bin/VBoxManage
# If you are running Cuckoo on Mac OS X you have to change the path as follows:
# path = /Applications/VirtualBox.app/Contents/MacOS/VBoxManage

# Default network interface.
interface = vboxnet0

# Specify a comma-separated list of available machines to be used. For each
# specified ID you have to define a dedicated section containing the details
# on the respective machine. (E.g. cuckoo1,cuckoo2,cuckoo3)
machines = cuckoo1

# If remote control is enabled in cuckoo.conf, specify a port range to use.
# Virtualbox will bind the VRDP interface to the first available port.
controlports = 5000-5050


[cuckoo1]
# Specify the label name of the current machine as specified in your
# VirtualBox configuration.
label = cuckoo1

# Specify the operating system platform used by current machine
# [windows/darwin/linux].
platform = windows

# Specify the IP address of the current virtual machine. Make sure that the
# IP address is valid and that the host machine is able to reach it. If not,
# the analysis will fail.
ip = 192.168.56.101

# (Optional) Specify the snapshot name to use. If you do not specify a snapshot
# name, the VirtualBox MachineManager will use the current snapshot.
# Example (Snapshot1 is the snapshot name):
snapshot = Snapshot1

# (Optional) Specify the name of the network interface that should be used
# when dumping network traffic from this machine with tcpdump. If specified,
# overrides the default interface specified in auxiliary.conf
# Example (vboxnet0 is the interface name):
interface = vboxnet0


'''

then to avoid the reason of ip, i check the ip conf of guest and ping the host machine.

Solution

I have already solved this problem. The reason is I start virtualbox as root,but I start cuckoo as user. Because of power management of unix，so normal user can't monitor root. So I start virtualbox with normal user. It's over.