"This Word document may look different"

Virtually every time I open a Word document in Pages (version 5.2) I get a box saying:

"This Word document may look different. Here's a list of what changed when you opened it in Pages."

That line is followed by something like "The font Calibri isn't available in OS X. It was replaced by Trebuchet MS."

Unfortunately, there is no option to click to keep this from displaying again, so I'm constantly closing these redundant warnings. Is there ANY way I can stop this? It's getting really annoying.