@Jeff – it seems this is a remnant of a 3rd-party plug in for InDesign on Windows. To get rid of the message you could export to IDML and re-open the IDML file in InDesign.
You can strip out the plugin info by sending the document through .idml.
What sort of file are you trying to relink?
OK thanks, I'll try that.
There were various file types (.ai, .eps, .tif) I did figure out the re-linking issue after I posted the message.
So what was the relinking problem, and how did you solve it? Your answer may help another user in the future.