2.1.0 combat crash

That damned wolertinger again! Was on the level 11 boss thinking I was safe from casting bugs but no!

win 7 still

version 2.1.0


############################################################################################
FATAL ERROR in
action number 1
of Step Event0
for object obj_battlecontroller:

Push :: Execution Error - Variable Index [0,-1] out of range [1,13] - -5.creatureList(100003,-1)
at gml_Script_bc_CreatureCast
############################################################################################

stack frame is
gml_Script_bc_CreatureCast (line 0)
gml_Script_bc_CreatureCastSpellGem
gml_Script_bc_ExecuteEvents
gml_Object_obj_battlecontroller_Step_0

Think I found the problem here - thanks!