Error when adding devices with dmd

Hi, I have this script which work :

 dev=dmd.Devices.Network.Switch.createInstance(ip[0])
 dev.setPerformanceMonitor('localhost')
 commit()

With "ip[0]" the IP address of my devices contain in a file. The problem is : when the device is add to Zenoss, the device name is the IP address, and it have no Ip in the raw "IP Address" so my snmp don't work. If I had it manually it works but there are more than 200 devices. What's the problem ?

Thank you for helping