When you save a CSP in Photoshop, you need to click Save As and change the file type to tga. Clicking Save makes it use the default format, psd, which isn't usable.
I checked to make sure it was a TGA before saving it.
I'm not sure where I'm messing up exactly but I follow these steps
Open Photoshop
File > Open > NEW CSP BATCH > mario3_big.tga
Image > Mode > Change to RGB(Index is usually checked) > Index
Local (perceptual) > I either use 72 or 256 colors > Black and White > Transparency checked
Image > Color Table > change Transparency to FF00FF
Save as mario3_big.tga > Open Meow Mix CUPASH step 2 > big mario 3 does not have an index palette
@mnsg For checking is its reconizing as Index I'm not sure how to check that. If you mean the little box on the right hand corner of the screen with the picture that says Index(theres also a lock icon next to it) then yes
I have tried leaving the Transparency box unchecked and als tried having the transparency on and not editing it at all in the color table.