They work for me on all the Macs I have access to right at the moment. There are no settings with regard to the use of arrow keys. They either work or they don't. Why they're not working for you in Bridge is a mystery.
I assume you've tried all the usual things like restarting the Mac, logging in as a different user, trashing the Bridge preferences, etc.
Start Adobe Bridge and immediately press Command+Option+Shift (Mac OS) until the Reset Settings dialog box appears. Select all three options--Reset Preferences, ResetStandard Workspaces, and Purge Entire Thumbnail Cache. Then click OK.