Zenping not started

Hello,

I would like to ask for your help with the following problem because it does not start the daemon Zenping, attached log.

2015-01-31 18:15:58,986 INFO zen.ZenPing: started
2015-01-31 18:15:58,994 INFO zen.ZenPing: Connecting to localhost:8789
2015-01-31 18:15:59,004 INFO zen.ZenPing: Connected to ZenHub
2015-01-31 18:15:59,011 INFO zen.ZenPing: _configCycle fetching configuration
2015-01-31 18:15:59,011 INFO zen.ZenPing: fetching monitor properties
2015-01-31 18:15:59,031 INFO zen.ZenPing: completed "fetching monitoring properties" request in 0.02 seconds
2015-01-31 18:15:59,032 INFO zen.ZenPing: getting threshold classes
2015-01-31 18:15:59,035 INFO zen.ZenPing: completed "getting threshold classes" request in 0.00 seconds
2015-01-31 18:15:59,036 INFO zen.ZenPing: getting collector thresholds
2015-01-31 18:15:59,090 INFO zen.ZenPing: completed "getting collector thresholds" request in 0.05 seconds
2015-01-31 18:15:59,091 INFO zen.ZenPing: fetching default RRDCreateCommand
2015-01-31 18:15:59,093 INFO zen.ZenPing: getting ping tree
2015-01-31 18:16:05,320 INFO zen.ZenPing: Deleting PID file /usr/local/zenoss/zenoss/var/zenping-localhost.pid ...
2015-01-31 18:16:05,321 INFO zen.ZenPing: Daemon ZenPing shutting down
2015-01-31 18:16:05,322 ERROR zen.ZenPing: Configure failed: [Failure instance: Traceback (failure with no frames): : Connection to the other side was lost in a non-clean fashion: Connection lost.
]
2015-01-31 18:16:05,327 INFO zen.ZenPing: Rescheduling configuration check in 21600 seconds
2015-01-31 18:16:05,337 ERROR zen.ZenPing: [Failure instance: Traceback: : 'NoneType' object has no attribute 'pjgen'
/usr/local/zenoss/python/lib/python2.6/site-packages/Twisted-8.1.0-py2.6-linux-x86_64.egg/twisted/internet/defer.py:186:addCallbacks
/usr/local/zenoss/python/lib/python2.6/site-packages/Twisted-8.1.0-py2.6-linux-x86_64.egg/twisted/internet/defer.py:328:_runCallbacks
/usr/local/zenoss/python/lib/python2.6/site-packages/Twisted-8.1.0-py2.6-linux-x86_64.egg/twisted/internet/defer.py:289:_continue
/usr/local/zenoss/python/lib/python2.6/site-packages/Twisted-8.1.0-py2.6-linux-x86_64.egg/twisted/internet/defer.py:285:unpause
--- ---
/usr/local/zenoss/python/lib/python2.6/site-packages/Twisted-8.1.0-py2.6-linux-x86_64.egg/twisted/internet/defer.py:328:_runCallbacks
/usr/local/zenoss/zenoss/Products/ZenStatus/zenping.py:266:pingCycle
]
Traceback (most recent call last):
File "/usr/local/zenoss/python/lib/python2.6/site-packages/Twisted-8.1.0-py2.6-linux-x86_64.egg/twisted/internet/defer.py", line 328, in _runCallbacks
self.result = callback(self.result, *args, **kw)
File "/usr/local/zenoss/zenoss/Products/ZenStatus/zenping.py", line 266, in pingCycle
self.pingTreeIter = self.pingtree.pjgen()
AttributeError: 'NoneType' object has no attribute 'pjgen'

thanks.