Hola, es probable que no tengas el archivo "colocado" en el lugar adecuado, hay que colocar el archivo del plugin en la carpeta de archivos comunes de adobe y no en la de plugins del photoshop
Te lo pongo en inglés que ahora ando algo justo de tiempo, de todas formas es fácil de entender.
Windows®:
1. Exit Photoshop CS2 and Adobe Bridge.
2. Open My Computer.
3. Double-click Local Disk (C:).
4. Navigate to Program Files\Common Files\Adobe\Plug-Ins\CS2\File Formats.
5. Move the existing Camera Raw.8bi plug-in to another location (for example, a new folder on your
desktop). Ensure you keep this version in case you need to revert back.
6. Copy the Camera Raw plug-in, Camera Raw.8bi, from the download into the same folder as Step 4.
7. Launch Photoshop CS2 or Adobe Bridge.
Mac:
1. Exit Photoshop CS2 and Adobe Bridge.
2. Open the Finder.
3. Navigate to the root of the local disk (not the user’s home folder).
4. Navigate to Library/Application Support/Adobe/Plug-Ins/CS2/File Formats.
5. Move the existing plug-in to another location (for example, a new folder on your desktop). Ensure
you keep this version in case you need to revert back.
6. Copy the Camera Raw plug-in, Camera Raw, from the download into the same folder as in Step 4.
7. Launch Photoshop CS2 or Adobe Bridge.
Un saludo