Really? In previous versions, screenpacks and lifebars would crash IKEMEN if I tried to use them directly without any messages. So I just gave up after a few tries.
Spoiler, click to toggle visibiltyThat is not necessary to open a mugen screenpack, mugen screenpacks should work without doing that, it will only not show Ikemen Go features or options in the Options menu.
What you describe is if someone wants to use Ikemen Go Features in a Mugen screenpack, which is pretty much recommendable since the intention of moving from Mugen to Ikemen GO is using all the features.
Now if OP is talking of Ikemen vanilla, yes, you have to port the screenpack.
The best option is to check Ikemen Go log file. Also, test a clean install to confirm if the PC can run Ikemen Go.
The dream is nothing yet drive us to the end.