Hello,
Snexxx.zip/Rar <-- other (homebrew)
Try This, /psp/ (where you downloaded "AS IS", so it be kinda like this,
inside the unpacked folder, /SNESXXX/psp/game/SNESXX/EBOOT.PBP, extra files,
Copy the extra Files and re-pack them to INSTALL.ZIP, but leavening the EBOOT.PBP,
so we have file named as INSTALL, then copy folder gamename to just 1 file and that is
SNESXXX/EBOOT.PBP but where leaving the other files. because we have it as INSTALL,
now copy those file/folders to desktop and Pack those as SNES1234.ZIP see if that helped.
If a error on unpacking, (blacksreen) then exit game then download psp filer v6.6,
To Do, pspfilerv6.6.rar, unpack to desktop, copy /pspfiler/EBOOT.PBP, rename the second folder/file to (the extra folders to)
INSTALL.ZIP repack the PSPFILERV6.6/EBOOT.PBP with install.zip like pspfilerv6.6/eboot.pbp and install, pack those to PSPFILER.ZIP and place to your game exploit name NPUHXXXXX/ find SNES1234.zip
copy those to your game folder and enjoy

. Hope that helps...