Keywords are not being saved

I am new to Adobe Bridge and using Digital Asset Managers in general. I am trying to use Bridge to organize my person photo/video collection using the Keywords system.

However, for most of my images that I try to apply a keyword to, it just isn't being saved (no error messages at all). The check box will fill in just fine, but if I deselect the image and select it again, there are no keywords applied.

I've tried a few different combinations of the Keywords settings but none of them seem to work any differently.  Is there something else I need to be looking at?