Re: I had a power failure and I am now informed that there is a problem with the cache and that I have to go to preferences, purge the cache. I've done this, but get same error message every time I open Bridge subsequent times.

Mac or PC? OS version? Which version of CS?

Have you tried resetting Bridge? Ctrl (Windows) / Opt (Mac) + click the Bridge icon to start, and select appropriate boxes.

Failing that, you could manually delete the cache, but we need to know answers to the questions to say where it is.