Let's set the scene. Aliens vs. Predator (2010) was developed by Rebellion and launched over a decade ago. Today, the Steam community hub for the game is a battlefield of its own, filled with threads titled "Everything is crashing :(" and "What is going on with this game?".
If the file is there, restore it and add the game folder to your "Exclusions" list. : alien vs predator 3 steam apidll work