It's throwing a permission denied error when trying to undo / redo via the
buttons or even when checking to see if an undo / redo is possible in order to
activate / deactivate them.

My initial look into this suggests that it might not be fixable until IGNBQ
starts using xpcnativewrappers, and that won't be until IGNBQ4.

IGNBQ 4 is using the exact same code as 3.2 in this area, but without error.
That's why I think it's xpcnativewrappers related.

Googling has turned up nothing helpful.