I get the same error message / crash and a rapid fix or workaround would be highly appreciated! Otherwise, the game works fine and is still somewhat playable, although I had to unlock the 1950 starting time in one go…
For your information, the problem also occur on a fresh installation of build 4363 Mac-64bit. All save files are affected: autosaves and manual saves, including save files that do not contain changes of the generated map.
Mac OS X Lion 10.7.5 / 2.7 GHz Intel Core i5 / 8GB 1333 MHz DDR3 / AMD Radeon HD 6770M 512 MB (iMac mid 2011)