My boyfriend and I are having the exact same trouble; we both own the full Baldur's Gate series, with the same patches, and the ToB iteration of Easytutu installed in the same directories, with identical bgconfig entries. Windowed mode with alt+enter to stave off crashes, too. Yet upon him trying to join my hosted game, or my trying to join his, we are told that the server and client have different program versions. Gameranger and Hamachi return the same results. I'm nearing wit's end, I fear.