One of my customer developed with a store event sink (onsave;ondelete) in x64bit Exchange 2007 server. He want to know in which server role that we need to register the event sink along with COM+ application?
Yep, that's true. As you know in Exchange Server 2007 it has various server roles like hub, transport, edge etc.
The EventSink needs to be installed on the mailbox server role of the Exchange Server.