I tried to go back to the previous version of Camera Raw but this made no difference
Excuse me if you know how to do that, but I read many posts on the Adobe forum about incorrect installation of ACR.
Following is true only re Windows, CS3 (it is different from previous PS versions):
1. Camera Raw.8bi has to be placed in "Program Files\Common Files\Adobe\Plug-Ins\CD3\File Formats"
2. Any other version has to be *removed* from that folder (*not renamed*). I copy all versions in a folder named SavedVersions.
3. PS has to be restarted (not Windows).