A server had to be re-built after Hard drive crash.. After installing exact Image of the Server software, The WMI fails to connect when called (RPC Server is unavailable) from another computer. However, Can connect using Visual Studio (2005) Server Explorer.
The calling server is Windows 2000 server and the called is Windows 2003. Both computers firewalls are disabled and appropriate rights are assigned to the calling and called accounts.
Check both the server and the client's event logs for any suspicious entries that might suggest what is misconfigured. Also, check what are the identities of Visual Studio and the app that calls WMI and if they are not the same, what's the difference in their security configuration.
The culprit is simply the netbios name.. Prior to re-build the computer name was 'rulestream' After re-built some how it is given 'rulestream.myDomain.com' I was able to spot the difference using Sysinternals TcpView.. Thanks Sysinternals