No help, but a workaround: Whenever you are close to finishing SETI, disable wonder movies under "graphic options" in the "game" menu. Once SETI has been built, you can enable the movies again.
Since this only happens with the SETI wonder, there's a good chance that the problem rests with the video file itself (wonder26.avi). Have you tried playing it with an external video player like the one included in windows?
There is also the possibility that it's a problem of neither Civ2 nor the file itself. I used to get a reliable crash at a specific moment in the middle of the Oracle movie when playing the game under Windows95, but those crashes simply stopped once I switched to Windows XP.
Anyway, good luck!
