Or the possible bug that Traveller admited (due to several reports in the later pages thread
http://www.subsim.com/radioroom/showthread.php?t=203542 ) can be narrowed down with the difference between these two missions (meaning which units is contains).
It seems a good chance that one of the units in the mission "uss archer-fish" is not correctly working/spawning/loading. Make a mission for each of the units contained in this mission, and see which one fails to spawn or makes the game crash. That's how you test a bug in a mod. But then comes the hard part in digging for bugs. What is wrong inside those files!?!