That's ok, but if you uncheck Scriver in Options - Plugins, the default SRMM plugin will be loaded instead of Scriver, because Miranda always needs a message editor, even if no "third-party" plugins are chosen.
Wouldn't that mean that it's the default SRMM editor that's somehow causing my crashing problem? When I did a clean install of the 64bit portable, TabSRMM was already checked in the plugins list. I didn't see any crashes when pasting text. While trying to customize the interface back to how I had it before, I thought I was using scriver since that plugin was in my old install folder. I must have been using the default SRMM.
As it is now, if I disable both TabSRMM and Scriver in the plugins, It starts to crash again when pasting any text into message windows. If I use either TabSRMM or Scriver, it's fine.