IOS236 is just a backup of IOS36
Grabbing the newest version of IOS36 will probably result in it no longer being trucha signed and therefore blocking any homebrew that uses it.
I'm not sure what causes this though.
What exactly do you mean with unload? like hit home and then click "Wii menu" (or whatever the button says)?
I recall having this myself sometimes but I'm not too bothered since I just reboot my wii if I want to play another game (that way I directly end up in CFG loader rather then my system menu from which I'll need to open CFG loader)