I would guess that the CS or PS installation is corrupted and an uninstall of everything Adobe, clearing the preferences, running the CSCleaner script and a re-install might fix things.
Installs can become corrupted if beta and release versions of the same product have been installed or if a mixture of single-purchase-apps and suite-bundled apps are or have been installed on the same system, where, for example, Bridge is looking for the bundled version of PS while the PS actually installed, now, is the single-app-purchased version, and Bridge is looking the wrong place to confirm PS is there.
It also could be that Bridge is seeing an expired license for a beta or other-purchase-model version that knows that app is no longer installed. If CSCleaner doesn’t fix licensing issues, then maybe there is a different thing to do to reset licensing.