Hi Ajinkya,
You are correct, any time that you attempt to access a remote OPC Server you will have to configure DCOM on both the client (PCo) and the server (OPC Server). The Cimplicity HMI product should have a document available to provide guidance on configuring DCOM for OPC DA connectivity. If not, look at this document:
However, it may be required to configure DCOM in order to satisfy customer security requirements.
Regards, Steve