Probably something really obvious but I can't figure it out. Need to stop asking questions or I'll never finish.
Please help me

Here is the code that crashes my game:
___________________________________________
############################################################################################
FATAL ERROR in
action number 1
of Other Event: Room Start
for object objWorld:
Variable objWorld.rMiku(100007, -2147483648) not set before reading it.
at gml_Script_scrGetMusic (line 14) - case rMiku:
############################################################################################
--------------------------------------------------------------------------------------------
stack frame is
gml_Script_scrGetMusic (line 14)
called from - gml_Object_objWorld_StartRoomEvent_1 (line 4) - scrGetMusic(); //find and play the proper music for the current room
Thank you! (I should really do some research on this)