Which camera exactly?
By re-installing CS5, you've reverted back to Camera Raw version 6.0 which shipped with CS5.
Your camera probably requires a later version of Camera Raw. In Photoshop, try Help > Updates.
I am sure you are correct. I have tried to update, but it continually fails on download. I really hate adobe and the way they can care less about their older customers. I waited 20 min, to chat with a "customer service expert" only to be told they won't talk to me unless it is about the latest version. I am un-installing and re-installing to try again to upgrade.