Hmmm.... since the new files in 1.1 are in a somewhat changed form, (certainly not all values in the file, but some of them) using old file values will of course crash when attempting to load. I found that out in 5 minutes after upgrading and then looked at the forum, where i believe Annatar explained the somewhat changed file values. As to changing those values? It may mean using the new developer.exe to get those old files where the values have changed to reflect those new values. Two or three lines i am guessing at this point, because not all the values changed. And then resaving them.
I'm not sure if the map editor in 1.1 is the same as the one in 1.05, but if it is new for 1.1 then that may fix your maps. As to save games? I am not sure there is a save game editor at all, though i could be sorely mistaken. Some one else much more experienced in the community may have an answer to that for you. I realize this may have been little help and i am sorry for that, but did want to try to help. At this point i think we are all facing the same situation. For me, i deleted all the save games and old mods, and am starting from scratch. It may not be the choice that you would do, but for me, it is cleaner.
Anyway, take care and hope someone with more experience gets you the help you would like,