You have one mode (like Multiplayer) set to English while another (Zombies or Singleplayer) is still set to Polish. Step-by-Step Fixes 1. Sync Your Languages (The "Rule of Three")
This error is notorious for appearing on both the Steam and Plutonium versions of the game, usually preventing the game from launching past the initial splash screen or causing an instant crash to desktop. Black Ops 2 Sound Bank Failed To Load Cmn-root.polish