I stumbled upon this page as I was going crazy trying to figure out why I could not get my X30 to fire the flash through the hotshoe. (I am using off camera flash through a radio remote.) The replies on this post got me to look at what I might have turned on by accident. And I then noticed a little yellow flower with a magnifying glass on the left side of my screen. I had no idea what it was but suspected it looked like a macro sign. Sure enough, I pressed the macro button on the back of the camera, that icon disappeared and the flash fired right up!
After testing this a little more, I noticed that if you have it set to normal macro (one press of the button), the flash fires. But if you have it on Super macro (two presses of the button) the flash will not fire.
This is a really frustrating thing because it is easy to hit that button accidentally and not notice it because it does not change anything in your normal shooting.
Thank you to the other repliers for sending me down this path!