Search results include old deleted topics

We use RoboHelp9 to generate chm Help files for our software documentation. We have

We have several RH projects and merge them together into 1 chm file (using helpmerger.txt to list individual RH projects).

I searched for a term today and in the search results were OLD topics from OLD RH projects that have been deleted. I get this:

This page can’t be displayed

• Make sure the web address //ieframe.dll/dnserrordiagoff.htm# is correct.
• Look for the page with your search engine.
• Refresh the page in a few minutes.

Why/how are these old topics still referenced?

Thanks in advance for your assistance.