Probably that you're using software that's over three years old and trying to process raw files from a camera two years old. You can make sure to update your camera raw / photoshop to the newest patch, and check your camera's compatibility with your version of Camera Raw. Or use Adobe's free DNG converter to convert the ORF files to DNG before processing, with no loss of quality.
Up until the release of CS5 that was the only version of photoshop I used and I was able
to open and process the very same raw files without any problems. That's what is so confusing.
The majority of problems with opening Raw files are one of 2 things.
Either the files are in the wrong place or you have more than one version in the file.
If my memory serves me correctly in CS3 to go PS click on help/p[lug ins/camera raw, or something like that. It will show the version. Make sure there is only one showing.
ACR should be in Program files/COMMON FILES/Adobe/ and then drill down to Bridge plugins