RPC unavailable error in Win 2003 serve

[Gautam]

I am using Dim oPort As Por
Dim oPrinter As Printe
Dim oMaster As PrintMaste

oPort = New Port(
oPrinter = New Printer(
oMaster = New PrintMaster(
' for adding the port---------------------------
oPort.ServerName = "\\" & strServerNam
oPort.PortType =
oPort.PortName = strPortNam
oPort.HostAddress = strHostAddres
On Error Resume Nex
oMaster.PortAdd(oPort
The error occurs at the above line. Please help

Thanks
Gautam.