While I won't provide a direct download link, I can guide you through the general process of downloading and installing Zone UI:
If you are on a private server (like X Labs or Iw4x ): Zone Ui.ff Cod Mw2 WORK Download
Select to let the launcher identify and replace corrupted assets. While I won't provide a direct download link,
Assuming you have a standard copy of Modern Warfare 2 (2009), follow this to avoid the "WORK Download" hunt: Zone Ui.ff Cod Mw2 WORK Download
Why does the game keep telling me ERROR: could not find zone: 'ui.ff?