I’m getting DCOM 10006 error between a SBS 2008 and a 2003 Standard Server.

The SBS 2008 Server reports ‘DCOM got error “2147944122” from the computer when attempting to activate the server’. Computer B is a Windows 2003 Standard Server. I’ve researched this problem and applied a change to the SBS 2008 Advanced Firewall as suggested. But the problem is still being reported on the SBS 2008.

Anyone have any suggestions as to what to change on the 2003 Server to fix this?