If you are using the mod (which usually runs on the "bio4.exe" version), you need to place the DLL manually.
By following the solutions outlined in this article, you should be able to fix the steam-api.dll error and enjoy Resident Evil 4 HD on Steam without any issues. Resident Evil 4 Hd Error Steam-api.dll
There are several reasons why you may be experiencing the steam-api.dll error while playing Resident Evil 4 HD on Steam. Here are some of the most common causes: If you are using the mod (which usually runs on the "bio4