I have also had this problem, and have submitted tickets for it. I saved many different game types to try and see if it was a particular setting, but I have not gotten any luck with that so far. Map sizes, settings, and custom races do not seem to matter. Autosaves do not load either.
I tried the game settings refresh they suggested, and tried lowering my graphics to make it easier on my computer to load (which seems to play it just fine at high settings).
So yes, I believe I have the same problem, and for what it's worth, this seems to have started with B5. During B4 I was able to load saves just fine. No solution yet, as far as I know.