Bridge and ACR are companions to either the payfor Photoshop or the payfor After Effects. The message means you need to open a raw file from either of those payfor products before you can open a raw file from Bridge, directly.
Assuming you have Photoshop, use Photoshop / Open and browse to a raw file and click Open (or Ok or whatever the button is) so that the Camera Raw plug-in starts up, then exit out of PS and start up Bridge and try your Open in Camera Raw, again.
If you feel you’ve done this, arready, then perhaps there is something wrong with the licensing processes on your Mac, and iw might be good to know what versions of Photoshop or After Effects you have along with what version of Camera Raw you’re using.
If you don’t have Photoshop or After Effects, then you’re not licensed to use Camera Raw.