Hi Liz,
This may sound stupid but did you try dragging the slider on the pop-ups just in case the data is displayed to the extreme right? This happened to me once because a particular field name was about 200 characters. Otherwise your data is being displayed alright on the table.
~ari
Thank you Ari...I think I was being too hasty. I had to re-publish the service and wait about 30 minutes, and then the pop-ups showed up as well as the table. But, thank you it's a really good tip!