No mod fixes that error. In fact, mods often cause it. Disable all mods, verify game files, then re-enable mods one by one.
Before you download anything, understand why the error appeared. The most common reasons for RE6 specifically are: Resident Evil 6 Steam-api.dll Fix Download
A Windows update, antivirus, or Steam client update detects the cracked DLL as malware and deletes it. Then the game tries to call the missing file. No mod fixes that error
Click . Steam will automatically detect and redownload the missing .dll . verify game files