Do you have over 1gigabyte of downloaded plugins? i have 1.5GB worth of plugins in my folder, so it crashes just as you have stated.
There's only one way that you can stop the game from crashing while saving, that is to organize your plugins folder. Put all the unwated Lots in a folder and trasfer them to another folder. Only put them back when you need them.
As for me, i'm halfway through with organizing my folder.
-Good luck! =)