I have gotten the (already reported) 'planet x is building nothing' report, as others have, but there is something else going on re: GNN.
Occasionally, the GNN report screen will come up and be blank; it is just the black background, with no text whatsoever. I'm sorry that I can't tell you precisely what was going on at the time; there were so many things, and, of course, no text to inform me.
I was playing a tiny/rare map with one opponent. I was the Drengin, and I was playing against the Torians, with no minors. This particular problem started in earnest in the mid/late game when I was building up my military in preparation for invasion, so it may or may not be related to ship completion notifications. (the ships in question were the stock transport and defender). I did receive a number of correct notices to that effect, so this problem may be unrelated, but I though that I would throw that in anyway.
Hope this helps to track this one down. Best of luck.