Did you put any conditional formatting on the fields in your portal? (Do you see the conditional formatting red and blue diamond attached to these fields in layout mode?)
If you click into a field that is formatted to make the text non visible such as the same color as the background color, you'll see the contents when you enter the field and then they will disappear when you exit the field.
You may just need to select the fields and specify a different text color on the inspector's appearance tab.
If all else fails, try creating a totally new portal.
So I looked at everything you mentioned, PhilModJunk, and no luck. I even created a new portal. That didn't work, either.
So I changed the field type from edit box to a drop down menu, and suddenly everything showed up. I changed it back to an edit box and everything seems to be working. I don't even pretend to have any ideas about why that fixed the problem ...
If anyone else has any ideas, I'd be glad to hear them. I haven't tried to replicate the problem in another file yet, but at least it's working now.