Me again. I just had an response from Adobe support that actually fixed my problem. I will paste it in here, but keep in mind that it was the answer given to ME for MY computer, so it may not work for you..... don't blame me or Adobe if it doesn't.
Read my previous post to get an idea of my situation.
Good luck, I hope it works for other people, too.
Here is my fix (the files were already in place, but opening the two versions of Photoshop is what did the trick):
"On Windows® Vista 64-bit, two separate versions of Photoshop are
installedin both 64 and 32-bit. When camera raw is installed, it must
be installed for both versions to work correctly. If you manually
installed the plug-in, please ensure you followed these directions after downloading the plug-in:
The CameraRaw.8bi found at the top level of the zip folder should be
placed in the following directory:
C:\Program Files (x86)\Common Files\Adobe\Plug-Ins\CS4\File Formats
The CameraRaw.8bi found in the folder labeled 64-bit should be placed in the following directory:
C:\Program Files\Common Files\Adobe\Plug-Ins\CS4\File Formats
You can access these instructions and the download for Camera Raw on our website. . To access the page, simply copy the following and paste it in the address bar of your web browser:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=4060
If this does not resolve the issue, it is possible that you have
launched one version of Photoshop but not the other, meaning the 64 and
32-bit versions. To ensure both have been launched, do the following:
1. Close out of Photoshop and Bridge
2. Navigate to C:\Program Files (x86)/Adobe/Adobe Photoshop CS4
3. Double click on Photoshop.exe
4. After the program opens fully, please close it.
5. Navigate to C:\Program Files/Adobe/Adobe Photoshop CS4
6. Double click on Photoshop.exe
7. After the program opens fully, please close it.
8. Launch Bridge from the icon you typically use and attempt open images in Camera Raw."