Basic shot in the dark here...
Since the server was moved & re-IP'd, it's possible that one or more WINS or DNS servers haven't picked up the change. And the change may not have tricked down to the local cache of the system where you're pushing the agent from.
Personally, I'd go through WINS & DNS, remove all references to the old IP, then replicate to all the other servers. At the BE server, do an IPCONFIG /flushDNS and an NBTSTAT -R.
Once you're sure that all forms of name resolution are working, retry it. I've seen scenarios where PING comes back correct (it's using DNS), while a failed app is using NetBIOS.