If you are emulating consoles within MAME (e.g., Sega Genesis via MAME's "megadriv" software list), you might see sp5001-a.bin errors due to misconfigured BIOS paths. Ensure your mame/bios/ folder contains the Sega System 16 BIOS set.
This is often seen as a revision "A" or "91" (838-13683-91). Troubleshooting & Usage in MAME Sp5001-a.bin Mame