Garbled startup screen in aes4all

Hello. I'd like to ask for help with a problem I'm having when trying to burn a copy of aes4all with aes roms (I've lost tons of blank cds trying and re-trying..)
I have no problems making a selfboot copy of the emulator with roms. However, when the games load, the SNK logo at the start (bios?) is garbled, and all the graphics in the games are garbled too. Otherwise, the text and sound effects of the games remain normal (but a game with totally garbled graphics is unplayable)
My question is: Do I have bad copies of the BIOS files? Bad game roms? Or is there something wrong in the procedure of converting the roms or burning the emulator? I've followed the tutorial on this site as closely as I can (I do end up with a bootable copy of the emulator; it's just that the games seem corrupted).
Thanks in advance for any help..

Sounds like you use an incompatible bios, not necessarily a bad one.

If you're unable to dump the console bios yourself, or don't have a console then you can use the uni-bios as a replacement.

Put the uni-bios (up to version 1.3) in the folder the readme mentions, prior to converting the roms to AES, convert, and then burn as normal.

Here's the link to the Unibios homepage: http://unibios.free.fr/