MP277 Communication with RSLinx OPC server

Hi,

I am trying to communicate Siemens MP277 HMI with RSLinx Gateway OPC server. The RSLinx Gateway OPC server is running on a computer. The computer and the MP277 HMI are on the same Ethernet network. I am able to ping the MP277 HMI from the RSLinx computer. I have configured the MP277 HMI connection as OPC with the RSLinx OPC server. The HMI in runtime gives error "Couldn't connect to RSLinx...". Has anybody tried this earlier. Your early response will be much apreciated.

-Arun