When a computer is part of a network, the DCOM wire protocol enables COM objects on that computer to communicate with COM objects on other computers. You can disable DCOM for a particular computer to help protect against this vulnerability, but doing so will disable all communication between objects on that computer and objects on other computers. It is advisable not to disable the service but to follow the security update/install patch as per the guidelines.

http://www.cisco.com/univercd/cc/td/doc/product/voice/c_callmg/osbios.htm