Hmm, okay. Well, this does jump out at me then, although it's often wildly inaccurate:
56% memory in use.
0 MB physical memory [0 MB free].
0 MB paging file [0 MB free].
0 MB user address space [69 MB free].
Write to location 00000008 caused an access violation.
Sometimes not having a pagefile set up on your machine can cause issues, but usually not at 56% ram utilization. I have 24gb of ram and no pagefile and no problems. But when I had 6gb of ram and no pagefile it would start giving me trouble at about 80% ram usage for the system (in a variety of programs, actually).
One of the things that is possible is that the save files are causing memory usage spikes due to your savegame just getting absolutely huge. We try to do garbage collections right before and after that, but sometimes it kills it anyway. It could be that you're exceeding the amount of managed memory space (about 800mb) inside the process, simply by having a massive game going. Or it could be that you're exceeding the 32bit windows program max size (about 3gb) if you have the option selected to preload all textures.
If you hit F3 while in game, you can look at the amount of managed memory in use there while you are in your game. If it's 500+ mb, then that might be the problem right there.
One solution might be to not compress your savegames, if that is a problem. It will use more space on disk, but that's about it. In order to compress your savegame, it has to first write the savegame into ram, then transcode that into a compressed format, then save that to disk, then clear both from memory. In the Advanced tab of the settings, there is a Don't Compress Savegames option -- perhaps that will help.