如题 打开提示cannot find extension package: caster 需要换gms吗

运行报错：
___________________________________________
FATAL ERROR in
action number 6
of Create Event
for object obj_persistent:
COMPILATION ERROR in code action
Error in code at line 2:
global._mus_titlescreen = caster_load('music/titlescreen.ogg');
^
at position 28: Unknown function or script: caster_load

没装拓展包当然提示错误
还有，没听说过gm8.5，所以你的问题我可能解答不了