The most common reason a downloaded save file fails to appear in your game is a regional mismatch. PS2 games are locked by region codes: North America PAL: Europe / Australia NTSC-J: Japan
Before we start downloading and importing, it's crucial to understand how PS2 save data is structured. On an original PlayStation 2, savedata is stored on a physical 8MB memory card inserted into one of the console's front ports. Each game's data resides in its own folder on the memory card's file system, named with an extension of the game's TITLE ID.
Downloads - PS2 Memory Card Save Files -Emulator- - The Tech