Have you edited your source from default? Just curious.
Pretty sure it is going to be in here.
Code:
SpellFinished(spellbonuses.SpellOnKill[i], this, 10, 0, -1, spells[aabonuses.SpellOnKill[i]].ResistDiff);
It would not hurt for you to start outputting exactly what is there when it happens, using log.out or such.