I have heard some rumours that a Nvidia card causes more crashes than an ATI card when playing MTW. As most of the crashes seem to be happening when going into battle, its certainly a possibility, now I am no techie or anything but this is what I suspect may be the case. I am running an ATI card on a fairly high end machine and although I do not have BKB's latest version of his mod, I have the previous one (super Late) and I have only come across the very occasional CTD. Although if BKB is running a Nvidia card then that theory goes out the window.
There are things you can do in game to make it a bit more stable (and this goes for all versions/mods) like turning off autosave and only quicksaving at the start of the turn (I know its annoying, but it must be done!)

Failing that, there are always the more generic problem fixers, such as uninstalling MTW, running a disk defrag and then reinstalling over the top. This will result in better performance for all games, the difference is really noticeable for high end fps such as Doom 3/HL2 and it may fix some of your problems, especialy if you haven't done it for a while. You can also try downloading the latest video drivers for your card. If you have already tried these, then well I don't know