Yes, there is some sort of error that can occur if you save a game, play, save again then try to reload the original save game without quitting SE4. I forget all the particulars though.
Do a search of the forum for save game problems. There was a very detailed explanation posted about 4-6 weeks ago, right after patch 1.35 came out I think.
I think this is the link to the thread.
http://www.shrapnelgames.com/ubb/For...ML/002477.html
[This message has been edited by Marty Ward (edited 05 June 2001).]