Yes. It is obviously the FloorPlan app giving you the error, but it's misreporting the error.

Open an Explorer window. Click Tools->Folder Options. Then click "File Types". Find your BMF extension, click on it, and select Advanced. Click on the "Action" that is in boldface and click "Edit". Examine the "Application used to perform action". Now do the same thing on the other computer and compare the final results. Are they the same or different?

Either way, I think you should probably contact FloorPlan's tech support. It really sounds like v8 was not removed properly.