There is now patch available to workaround an error inside the memory management of Windows 2003. So a patched OpenSHORE server is now running on Windows 2003 without trouble. I will release this workaroud with the next server version (Beta 3). See:
http://sourceforge.net/tracker/index.php?func=detail&aid=1253486&group_id=65882&atid=512595
Regards, Helge