What else could I try to get the raw files to open?
What camera are the camera raw files from?
First make sure your camera model is supported. If not you may have to convert them to dng (digital negative file format).
See this help file for the camera list and required ACR version.
The Canon PowerShot S100 should be supprted in photoshop cs5 with camera raw 6.7, which is the latest for photoshop cs5.
If you go to
mac Photoshop>About Plug-In>Camera Raw
windows Help>About Plug-In>Camera Raw
what version does it say?