A friend of mine is having trouble playing Spring. I'm able to host games, and he can connect to me without sync error in the lobby, yet he can't actually play, in Spring SP, or the regular game.
He's running a Dell system, with integrated graphics and a 3.0 GHz P4.
He's got everything on minimum, all features turned off, and resolution set to 640x480. He's able to play all current games, including HL2, Dawn of War, etc., on low settings.
When he played via Spring SP, the map would kick him to the SpringSP client before he started pathing. In the regular lobby, he crashed back to the chat and remained synced.
He didn't receive any error messages, and we tried this with AA 2.1 as well as XTA.