Make sure your ACR (Adobe camera Raw) plug-in is fully updated. That camera model has been supported since Adobe Camera Raw 6.2.
DO NOT rely on the Adobe auto updater to tell you that there are no updates available. It's totally unreliable in CS5 and earlier versions. The Adobe updater team overseas did not get their act together even halfway right until CS6.
Go into the About Plugin > Camera Raw… menu item in Photoshop to see what version of ACR you have. In CS5, ACR should be at version 6.7, more precisely at 6.7.1.
If you are already updated to ACR 6.2 or higher, then go to the Tools menu in Bridge and Purge Cache for the offending folder(s).