Check earlier in this thread, we tried running with the Vista firewall completely disabled (as well as stopping its service and all associated services).
I'm not even convinced this is a directplay7 emulation issue. I suspect it goes deeper to the actual windows sockets implementation in Vista. (wsock32.dll - a primary dependency of StarFleetOP.exe which in turn depends on ws2_32.dll [windows sockets 2])
Interestingly, I cannot find any of the directplay dlls in the dependency list for StarFleetOP.exe at all. (as generated by HeavenTools' PE Explorer)