I have installed the latest version now available (not beta anymore) SIP Plug-in on several computers and in several networks with Series 60 SDK 2.0 (not 2.1) and have experienced the same, following kind of problems.
The SIP Server Emulator works ok (I guess), since I can add the "realm" domain and start the server. I have managed to run and setup the network connection with the SIP Plug-in included Ethernet plugin (I have also checked that it is exactly the same package as the separately available plugin at Forum Nokia). I have also managed to setup the SIP configuration on both S60 emulators (have tried both on one computer and two). I have also added the pc's ip to the domains list, since I have also tried the pc's ip as the realm like it was advised in the older, beta instructions.
The problem arises when I run the Warship application. No matter if I am running one or two emulators and how I start the application (one or both at once) the result is the same. The application tries to register itself to the SIP Server Emulator, so it sends a REGISTER message. The problem is that apparently the SIP Server Emulator does not respond with an OK message. As there is no response, the SIP application tries again, but adds a "via" field in the REGISTER message. This keeps on going until there are so many "via" fields that the SIP Server Emulator responds with a "Too many hops" message. Simultaneously, this halts everything else but the log window in the SIP Server Emulator with the intense REGISTER message repetitions (so the log window scrolls at huge speeds). When I disable the log, the halt disappears and the S60 emulator says that registering failed, and do you want to try again.
One other thing: why does it say in the instructions that you cannot use "subst" in Windows XP with the Ethernet plugin? I have tried installing the Ethernet plugin in Windows XP computers with both the subst in use and not and noticed no difference in its functionality, the "network_config.bat" works both ways. The Ethernet plugin, as I can see it, just installs itself to the c:\symbian\7.0s\series60_v20 but it naturally becomes available also on the substed drive.
Please help. I would be very anxious to try the only example application. Thanks for any help.