Oh, that's a known issue when people overload EMU with notes by looping them from Logic. But luckily we already know how to avoid it, just ensure you have your MIDI input off:

Remembering when a couple of years we faced with it first time - it was a real pain, but one mate found the way out and we still are using it :) You even can literally find that topic here with many-many pages of struggling :) mmmm, nice to remember it, thanks for the reminding :)
Ethan Kennedy
Hi, I'm experiencing issues with EMU crashing when switching between programs using MIDI notes.
It has only been happening recently, and I don't know why. I am fully up to date with my Mac, and EMU. And I feel like I am running everything as it should be run, as I have never occurred this many crashes before. It is literally crashing and giving me the colour wheel everytime Logic communicates to it to change programs.
Any help would be appreciated!