I was playing your newest version, then started getting this whenever i right clicked

___________________________________________
############################################################################################
FATAL ERROR in
action number 1
of Mouse Event for Glob Right Button
for object objPlayer:

Push :: Execution Error - Variable Index [20,0] out of range [20,-1] - 101025.inventory(100048,640000)
at gml_Script_RemoveItem
############################################################################################
--------------------------------------------------------------------------------------------
stack frame is
gml_Script_RemoveItem (line 0)
gml_Object_objPlayer_Mouse_51

Same happened to me:

___________________________________________
############################################################################################
FATAL ERROR in
action number 1
of Mouse Event for Glob Right Button
for object objPlayer:

Push :: Execution Error - Variable Index [20,0] out of range [20,-1] - 100969.inventory(100048,640000)
at gml_Script_RemoveItem
############################################################################################
--------------------------------------------------------------------------------------------
stack frame is
gml_Script_RemoveItem (line 0)
gml_Object_objPlayer_Mouse_51

Thanks for the feedback! Going to fix these soon!