MSDTC unavailable

Hi,

I need to use transaction support with linked server. Linked Server is created for SQL Express 2008 R2 Express.

MSDTC is enabled on Linked Server (Windows 7 PC) as per http://technet.microsoft.com/en-us/library/cc753510(v=ws.10).aspx.

While connecting the SQL server, I get an error : "MSDTC unavailable.."

Is there any guideline for configuring transactions for Linked Server?

Thanks.