Something is wrong with your install. Did you happen to uninstall anything relating to ACR/LR after your CS5 install? I would suggest reinstalling. You might get away with downloading and installing the DNG 6.6 installer and see if that brings back the profiles.
Thanks Jeff, but this computer Win 7, 64 bit, had Photoshop CS4 installed before. I uninstalled Cs4 prior to the CS5 install. That may have been the problem here. Although I won't miss the camera profiles that are missing (Adobe Standard in particular) you most likely are correct on why they are not listed. Thanks for your reply.