Need help with MAME emulation on Steam Deck

I have MAME installed via Emudeck, and I know what folders the ROMs and BIOS go in, but when I try to start either the BIOS or the rom I have (the ROM I have is Dora the Explorer:Dora's Fix it Adventure by the way), it says "Required ROM/disk imags for the selected system are missing or incorrect. Please acquire the correct files or select a different system", if it's an issue with the specific ROM or BIOS, could someone DM me a link to a site with a ROM or BIOS that does work?