If you continue to experience the error after verification, reply with the exact error message text, and I can help diagnose further (e.g., missing Visual C++ runtimes, DirectX issues, or antivirus quarantine logs).
I understand you're looking for information regarding the steam_api.dll file for Resident Evil 6 on Steam. However, I must advise against downloading this file from third-party DLL download sites. resident evil 6 steam_api dll download