John - I am pretty sure you can place a PDF. OK I just tried it and it works fine.
I exported the same set of objects as Illustrator *.eps and got the resulting error message. This may simply mean that Designer is not creating a preview image. But the PDF works fine and so why bother with the EPS?
The AI extension creates a file that can also be edited. But I got the same error message in InDesign CS5.
FWIW - I was able to open edit both my exported EPS and AI files in Illustrator so the files are good and will most likely output from InDesign but you won't have a preview.
So, PDF is the way to go.
Bookmarks