OK, now I'm baffled. I did some more checking, and, on my computer, ai and pdf can be viewed in the preview pane, but also, SOME eps files can be viewed, but not all. No matter location (local or network) or size, Doesn't seem to be any reason why some will and some won't. I tried cdr also, and it said "no preview available". I does not say that when eps can't be viewed. Weird!
Mark