Okay, a little history just in case it helps:
Recently I had a 2.6fw, and up'd it to 2.71, applied HEN_C correctly, and downgraded to 1.5 correctly. I forget if I did / was able to play roms while still in 2.71, but I doubt it. But of course I did in 1.5.

Tonight I did something different, and it's causing me to get the "game can not load" error. I did two things: put a .cso (legal backup on, but before I checked to see if it was kosher, I used a corrupt-file remover. I believe the name is: PSP C-D Remover. Oh yeah, and I went back and deleted the HEN_C picture files (thinking I didn't need ;/), as well as the sample files that come with it. I started from scratch twice -- reinstalling the HEN_C .tiff file, upgrading to 2.71, and downgraded to 1.5.

I don't know what the hell I did wrong, and I've spent a nice amount of time trying to fix. Any help on informing me wtf I did wrong and htf I can fix it would be very appreciated of course. I must be overlookin' something...

UPDATE!
Nevermind, fellas, I got it now. Thanks anyways.