If you download a random ZIP file labeled sf2.zip and MAME 0.78 says "Missing ROM or CHD images," your ROM is likely from a newer set. Only 0.78-specific dumps will work.
Because we cannot host links to ROMs directly, here is the workflow to find a correct set: Mame 0.78 Roms Download
25 Jan 2022 — GitHub - libretro/mame2003-libretro: MAME 0.78 for libretro. Compatible with MAME 0.78 sets. GitHub. MAME Reference Sets | pleasuredome - GitHub Pages If you download a random ZIP file labeled sf2