Hey, sorry for another necro here. For anyone who is still using the script, or Dargor if you are still around, I found a bug in the script. This bug is concerning the 'Avenger' overdrive mode. When a party member is knocked out in battle, even if there is no party member with Avenger mode selected, the game will crash.
The problem comes mainly from the part of code around Line 503. Inside the 'for' loop, all references to 'user' should instead be 'member', like in the Comrade overdrive mode. This is because, for the case of Avenger mode, 'user' is normally going to be an Enemy rather than an Actor.
Additionally, on Line 140, again 'user' should be changed to 'member'.
Making these changes fixes the bug. I hope this is of help to someone

Aside from this, the script is great, good job Dargor!