It appears that the only thing in my Oblivion setup that uses C++ is OBSE. I am running maybe 25 mods, most of them off the top 100 list at TESNexus, and most of them use OBSE. I have tried running Oblivion through the launcher instead of OBMM, which doesn't load and run OBSE. When I do I can loot and proceed and do whatever, then save the game and that save will load without error, as long as I run Oblivion through the launcher. Running Oblivion through OBMM again, which does launch OBSE, will result in that last save erroring out on load. Note that the mods are all still enabled both ways, they just don't work without OBSE.
I have previously posted a question about this on the Nexus Forums, to which I got one reply in three weeks. That reply, while he was sympathetic, wasn't very helpful, so this is apparently not a real common problem. I'm hoping someone here can give me at least a hint about what could be causing this, or better yet some idea of how to fix it. I can post my load order if that would be useful.
At this point my options seem to be to play Oblivion without OBSE and the mods, which is pretty much a non-starter, or not play at all. Any assistance will be appreciated. Thanks for your time.