Plug-in Doesn’t Find Text Which Should Be Replaced

I’m attempting to change a URL throughout my blog, roughly 200 pages.

When I run this plug-in in test mode it reports it doesn’t find any instance of the URL I wish to change, even though they are all over my blog on many pages. I selected all tables to be searched, so I don’t know what else to do.

This is the third search and replace plug-in that has failed to work properly so my server becomes a suspect. If that is the problem, I have no idea what the problem might be, or how to ask my host about it. Any clues here?

Search And Replace DB did replace some URLs, while ignoring many others.

Thanks for your thoughts.