Do you really mean PS4? Or is it CS4?
What does it say in Helps About plug-in under ACR?
Try this from the Adobe download page:
To open a DMG file:
Double-click the file. This will open Disk Copy, which mounts the image on your desktop.
To install with Adobe Creative Suite 4 or Photoshop CS4:
Automated installation on Mac or Windows®:
1. Select Updates... from the Help menu
2. Follow the on-screen dialogs to download and install the latest available Camera Raw update
Manual installation on Mac:
1. Exit Photoshop CS4 and Adobe Bridge.
2. Open the download file and double-click Setup, and follow the on-screen instructions.
3. Launch Photoshop CS4 or Adobe Bridge.
Thanks for the reply. I already followed all those steps and there is
nothing int he knowledge base about this problem. I am using
photoshop 4 but is is not part of the creative suite.
It's called Photoshop CS4 – even if it's a stand-alone installation (look at the splash screen).
The path is described here in Adobe's instructions for a manual install:
"Drag the Camera Raw.plugin file from the Camera_Raw_5_5 disk image into /Library/Application Support/Adobe/Plug-Ins/CS4/File Formats. If you are prompted to overwrite or replace the existing plug-in file, then click Replace.
Note: This file path refers to the Library folder at the root level of the startup disk volume, not the Library folder inside a user's Home folder."