Failed to load spell resist disease_75.

If the problem is loading saved games, then there are only a couple of things you can even try. First, try disabling mods. I would start with ALL mods to see if that helps. If it does, then try them one by one to see if a particular mod causes the problem. The only other thing I can even suggest, is make a mod that guts the spell. That is, make it so the spell does, essentially, nothing, like maybe set it as a script effect to an empty script. Or, maybe just silence or invisibility. If there is a utility for Morrowind like Tes4edit for Oblivion, they you could, with some doing, gut the spell directly in the Morrowind.esm Master file. But, that would take some doing. Make sure the program has enough memory, or use some cleaning tool; there has to be Something out there for Morrowind that will do something.