Solved.

So googling about this tends to return stupid music results.

If I use any kind of compression, it shrinks from 600 some MB down to about 50MB or less. It begins loading, but after checking the memory card, it goes to a never-ending loading screen.

If I don't compress at all, it fails to load in the same way.

I used ultra-ISO to rip a .bin file from the actual game disc.

Could that be the problem? I usually just download them, but this game is somewhat hard to find.
EDIT

Solved. Don't know if I can delete my thread myself, though.

dont talk about isos. Please its against the rules.

Can somebody close this thread?

it's against the rules to talk about ISOs? That's wierd, especially because this is a legally OK problem, instead of piracy related... I wanted to rip my own game (which I succeeded in doing) instead of downloading one online.

Haha, if that's against the rules, sorry, but that doesn't really make sense anyhow. XD

Its just that this kinda talk leads to ISO talk. So there really isn't anyone at fault here.

I Hope DCemu Staff members will allow legal ISO discussion someday..

^^ YA RIGHT. Atleast not anytime soon.