Ouch! Ouch! Ouch!
That is a monumentally bad idea !
Never, ever point any software at the camera card—other than a dedicated photo downloading utility, or Windows Explorer/Apple's Finder.
It's not very wise to connect the camera directly to the computer.
This excerpt is from a long-gone post by the, lamented, and celebrated author Bruce Fraser:
Bruce Fraser - 4:17pm Jun 14, 04 PST (#5 of 21)
* • Drains the camera battery
• Runs the risk of the software you're using to open the images writing to the card and destroying the format
• Runs a small but significant risk of USB power frying the camera
• Slowest method known to mankind of getting images off a CF or SD card
If you have—misguidedly and unfortunately—done that already, first back up the image files on your computer, then immediately format the card in the camera, which will erase everything in the card and format it to a fresh, pristine state.
What ever possessed you to do a thing like that?
Had you done that to the card containing the raw files you can't open?
Do not be fooled by what the camera shows you anyway. The preview you see in the back of the camera when chimping* is not a preview of your raw file at all, but of the embedded JPEG that the camera creates right after you shoot and records inside your raw file. The histogram it shows you in the camera is not based on the raw data at all either, but on said embedded JPEG.
The same is true when you review or playback the images later on the LCD display in the back of the camera.
*Chimping is a colloquial term used in digital photography to describe the habit of checking every photo on the camera display (LCD) immediately after capture.
The phrase is most likely derived from comparison between the sounds and actions some make while reviewing images and those of an excited primate (Oooh! Oooh! Aaah!), or when a photographer is completely absorbed in the act of analyzing, admiring or proudly displaying a shot to others.
Again, just to prevent any misunderstanding: first download the image files to your computer. DO NOT point any viewing or editing software at the images while they are still on the card.
Chimping is OK, using the LCD in the back of the camera itself.
You definitely don't want any software from the computer creating temporary files on the card or otherwise writing to the card.
It most certainly sounded that way to me:
What doesn't allow any changes?
Either in Windows Explorer or in Bridge you should be able to select (highlight) a file name and type a new one…
BOTH. Bridge disables it, while Explorer reverts back to the originial filename after the changes.