[Linux-cluster] help:can't execute Add a failover Domain

[lining at mail.ustc.edu.cn]

I have a cluster with two nodes ,it has started.
On the conga platform ,when I choose add a failover domain ,
it returned as followed:

Network station Error£º
this network station occured an error when handle your request.
the error is :
error type:
    AttributeError
error value:
    getFdomNodes

Enclosed my cluster.conf:
<?xml version="1.0"?>
<cluster alias="tvod" config_version="28" name="tvod">
        <fence_daemon clean_start="0" post_fail_delay="0" post_join_delay="25"/>
        <clusternodes>
                <clusternode name="10.0.3.232" nodeid="1" votes="1"/>
                <clusternode name="10.0.0.8" nodeid="2" votes="1"/>
        </clusternodes>
        <cman expected_votes="1" two_node="1"/>
        <fencedevices>
                <fencedevice agent="fence_vixel" ipaddr="10.0.0.8" name="fence"
passwd="123456"/>
        </fencedevices>
        <rm>
                <failoverdomains/>
                <resources>
                        <clusterfs device="/dev/mapper/vod-lv_vod"
force_unmount="1" fsid="Wf9iet-YGHm-dHM7-PSjW-CvVq-uOxJ-Y63hGd" fstype="gfs"
mountpoint="/1/" name="gfs" options="-t gfs"/>
                </resources>
                <service autostart="1" name="httpd">
                        <clusterfs ref="gfs"/>
                </service>
        </rm>
</cluster>

Thanks for helping !